com.google.javascript.jscomp.NodeUtil Maven / Gradle / Ivy
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/*
* Copyright 2004 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.base.Splitter;
import com.google.common.collect.AbstractIterator;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
import com.google.javascript.jscomp.NodeTraversal.ScopedCallback;
import com.google.javascript.jscomp.parsing.parser.FeatureSet;
import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.InputId;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.JSDocInfoBuilder;
import com.google.javascript.rhino.JSTypeExpression;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.StaticSourceFile;
import com.google.javascript.rhino.Token;
import com.google.javascript.rhino.TokenStream;
import com.google.javascript.rhino.TokenUtil;
import com.google.javascript.rhino.dtoa.DToA;
import com.google.javascript.rhino.jstype.JSType;
import com.google.javascript.rhino.jstype.TernaryValue;
import java.util.ArrayList;
import java.util.Collection;
import java.util.EnumSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
/**
* NodeUtil contains generally useful AST utilities.
*
* @author [email protected] (Nick Santos)
* @author [email protected] (John Lenz)
*/
public final class NodeUtil {
static final long MAX_POSITIVE_INTEGER_NUMBER = 1L << 53;
static final String JSC_PROPERTY_NAME_FN = "JSCompiler_renameProperty";
static final char LARGEST_BASIC_LATIN = 0x7f;
private static final Node googModuleDeclareLegacyNamespace =
IR.getprop(IR.getprop(IR.name("goog"), "module"), "declareLegacyNamespace");
// Utility class; do not instantiate.
private NodeUtil() {}
/**
* Gets the boolean value of a node that represents an expression, or {@code TernaryValue.UNKNOWN}
* if no such value can be determined by static analysis.
*
* This method does not consider whether the node may have side-effects.
*/
static TernaryValue getBooleanValue(Node n) {
// This switch consists of cases that are not supported by getLiteralBooleanValue(),
// which we will call if none of these match.
switch (n.getToken()) {
case NULL:
case FALSE:
case VOID:
return TernaryValue.FALSE;
case TRUE:
case REGEXP:
case FUNCTION:
case CLASS:
case NEW:
case ARRAYLIT:
case OBJECTLIT:
return TernaryValue.TRUE;
case TEMPLATELIT:
if (n.hasOneChild()) {
Node templateLitString = n.getOnlyChild();
checkState(templateLitString.isTemplateLitString(), templateLitString);
String cookedString = templateLitString.getCookedString();
return TernaryValue.forBoolean(cookedString != null && !cookedString.isEmpty());
} else {
return TernaryValue.UNKNOWN;
}
case STRING:
return TernaryValue.forBoolean(n.getString().length() > 0);
case NUMBER:
return TernaryValue.forBoolean(n.getDouble() != 0);
case NOT:
return getBooleanValue(n.getLastChild()).not();
case NAME:
String name = n.getString();
if ("undefined".equals(name) || "NaN".equals(name)) {
// We assume here that programs don't change the value of the keyword
// undefined to something other than the value undefined.
return TernaryValue.FALSE;
} else if ("Infinity".equals(name)) {
return TernaryValue.TRUE;
} else {
return TernaryValue.UNKNOWN;
}
case ASSIGN:
case COMMA:
// For ASSIGN and COMMA the value is the value of the RHS.
return getBooleanValue(n.getLastChild());
case AND:
{
TernaryValue lhs = getBooleanValue(n.getFirstChild());
TernaryValue rhs = getBooleanValue(n.getLastChild());
return lhs.and(rhs);
}
case OR:
{
TernaryValue lhs = getBooleanValue(n.getFirstChild());
TernaryValue rhs = getBooleanValue(n.getLastChild());
return lhs.or(rhs);
}
case HOOK:
{
TernaryValue trueValue = getBooleanValue(n.getSecondChild());
TernaryValue falseValue = getBooleanValue(n.getLastChild());
if (trueValue.equals(falseValue)) {
return trueValue;
} else {
return TernaryValue.UNKNOWN;
}
}
default:
return TernaryValue.UNKNOWN;
}
}
/**
* Gets the value of a node as a String, or null if it cannot be converted. When it returns a
* non-null String, this method effectively emulates the String() JavaScript cast
* function.
*
*
IMPORTANT: This method does not consider whether {@code n} may have side effects.
*/
public static String getStringValue(Node n) {
// TODO(user): regex literals as well.
switch (n.getToken()) {
case STRING:
case STRING_KEY:
return n.getString();
case TEMPLATELIT:
// Only convert a template literal if all its expressions can be converted.
String string = "";
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
Node expression = child;
if (child.isTemplateLitSub()) {
expression = child.getFirstChild();
}
String expressionString = getStringValue(expression);
if (expressionString == null) {
// Cannot convert.
return null;
}
string = string + expressionString;
}
return string;
case TEMPLATELIT_STRING:
return n.getCookedString();
case NAME:
String name = n.getString();
if ("undefined".equals(name)
|| "Infinity".equals(name)
|| "NaN".equals(name)) {
return name;
}
break;
case NUMBER:
return DToA.numberToString(n.getDouble());
case FALSE:
return "false";
case TRUE:
return "true";
case NULL:
return "null";
case VOID:
return "undefined";
case NOT:
TernaryValue child = getBooleanValue(n.getFirstChild());
if (child != TernaryValue.UNKNOWN) {
return child.toBoolean(true) ? "false" : "true"; // reversed.
}
break;
case ARRAYLIT:
return arrayToString(n);
case OBJECTLIT:
return "[object Object]";
default:
break;
}
return null;
}
/**
* When converting arrays to string using Array.prototype.toString or
* Array.prototype.join, the rules for conversion to String are different
* than converting each element individually. Specifically, "null" and
* "undefined" are converted to an empty string.
* @param n A node that is a member of an Array.
* @return The string representation.
*/
static String getArrayElementStringValue(Node n) {
return (NodeUtil.isNullOrUndefined(n) || n.isEmpty())
? "" : getStringValue(n);
}
static String arrayToString(Node literal) {
Node first = literal.getFirstChild();
StringBuilder result = new StringBuilder();
for (Node n = first; n != null; n = n.getNext()) {
String childValue = getArrayElementStringValue(n);
if (childValue == null) {
return null;
}
if (n != first) {
result.append(',');
}
result.append(childValue);
}
return result.toString();
}
/**
* Gets the value of a node as a Number, or null if it cannot be converted. When it returns a
* non-null Double, this method effectively emulates the Number() JavaScript cast
* function.
*
*
IMPORTANT: This method does not consider whether {@code n} may have side effects.
*
* @param n The node.
* @return The value of a node as a Number, or null if it cannot be converted.
*/
static Double getNumberValue(Node n) {
switch (n.getToken()) {
case TRUE:
return 1.0;
case FALSE:
case NULL:
return 0.0;
case NUMBER:
return n.getDouble();
case VOID:
return Double.NaN;
case NAME:
// Check for known constants
String name = n.getString();
if (name.equals("undefined")) {
return Double.NaN;
}
if (name.equals("NaN")) {
return Double.NaN;
}
if (name.equals("Infinity")) {
return Double.POSITIVE_INFINITY;
}
return null;
case NEG:
if (n.hasOneChild() && n.getFirstChild().isName()
&& n.getFirstChild().getString().equals("Infinity")) {
return Double.NEGATIVE_INFINITY;
}
return null;
case NOT:
TernaryValue child = getBooleanValue(n.getFirstChild());
if (child != TernaryValue.UNKNOWN) {
return child.toBoolean(true) ? 0.0 : 1.0; // reversed.
}
break;
case TEMPLATELIT:
String string = getStringValue(n);
if (string == null) {
return null;
}
return getStringNumberValue(string);
case STRING:
return getStringNumberValue(n.getString());
case ARRAYLIT:
case OBJECTLIT:
String value = getStringValue(n);
return value != null ? getStringNumberValue(value) : null;
default:
break;
}
return null;
}
static Double getStringNumberValue(String rawJsString) {
if (rawJsString.contains("\u000b")) {
// vertical tab is not always whitespace
return null;
}
String s = trimJsWhiteSpace(rawJsString);
// return ScriptRuntime.toNumber(s);
if (s.isEmpty()) {
return 0.0;
}
if (s.length() > 2
&& s.charAt(0) == '0'
&& (s.charAt(1) == 'x' || s.charAt(1) == 'X')) {
// Attempt to convert hex numbers.
try {
return Double.valueOf(Integer.parseInt(s.substring(2), 16));
} catch (NumberFormatException e) {
return Double.NaN;
}
}
if (s.length() > 3
&& (s.charAt(0) == '-' || s.charAt(0) == '+')
&& s.charAt(1) == '0'
&& (s.charAt(2) == 'x' || s.charAt(2) == 'X')) {
// hex numbers with explicit signs vary between browsers.
return null;
}
// Firefox and IE treat the "Infinity" differently. Firefox is case
// insensitive, but IE treats "infinity" as NaN. So leave it alone.
if (s.equals("infinity")
|| s.equals("-infinity")
|| s.equals("+infinity")) {
return null;
}
try {
return Double.parseDouble(s);
} catch (NumberFormatException e) {
return Double.NaN;
}
}
static String trimJsWhiteSpace(String s) {
int start = 0;
int end = s.length();
while (end > 0
&& TokenUtil.isStrWhiteSpaceChar(s.charAt(end - 1)) == TernaryValue.TRUE) {
end--;
}
while (start < end
&& TokenUtil.isStrWhiteSpaceChar(s.charAt(start)) == TernaryValue.TRUE) {
start++;
}
return s.substring(start, end);
}
/**
* @param n A function or class node.
* @return The name of the given function or class, if it has one.
*/
public static String getName(Node n) {
Node nameNode = getNameNode(n);
return nameNode == null ? null : nameNode.getQualifiedName();
}
/**
* Gets the node of a function or class's name. This method recognizes five forms:
*
* - {@code class name {...}}
* - {@code var name = class {...}}
* - {@code qualified.name = class {...}}
* - {@code var name2 = class name1 {...}}
* - {@code qualified.name2 = class name1 {...}}
*
* In two last cases with named function expressions, the second name is
* returned (the variable or qualified name).
*
* @param n A function or class node
* @return the node best representing the class's name
*/
public static Node getNameNode(Node n) {
checkState(n.isFunction() || n.isClass(), n);
Node parent = n.getParent();
switch (parent.getToken()) {
case NAME:
// var name = function() ...
// var name2 = function name1() ...
return parent;
case ASSIGN: {
// qualified.name = function() ...
// qualified.name2 = function name1() ...
Node firstChild = parent.getFirstChild();
return firstChild.isQualifiedName() ? firstChild : null;
}
default:
// function name() ...
// or
// class Name ...
Node funNameNode = n.getFirstChild();
// Don't return the name node for anonymous functions/classes.
// TODO(tbreisacher): Currently we do two kinds of "empty" checks because
// anonymous classes have an EMPTY name node while anonymous functions
// have a STRING node with an empty string. Consider making these the same.
return (funNameNode.isEmpty() || funNameNode.getString().isEmpty()) ? null : funNameNode;
}
}
/** Set the given function/class node to an empty name */
public static void removeName(Node n) {
checkState(n.isFunction() || n.isClass());
Node originalName = n.getFirstChild();
Node emptyName = n.isFunction() ? IR.name("") : IR.empty();
n.replaceChild(originalName, emptyName.useSourceInfoFrom(originalName));
}
/**
* Gets the function's name. This method recognizes the forms:
*
* - {@code {'name': function() ...}}
* - {@code {name: function() ...}}
* - {@code function name() ...}
* - {@code var name = function() ...}
* - {@code var obj = {name() {} ...}}
* - {@code qualified.name = function() ...}
* - {@code var name2 = function name1() ...}
* - {@code qualified.name2 = function name1() ...}
*
*
* @param n a node whose type is {@link Token#FUNCTION}
* @return the function's name, or {@code null} if it has no name
*/
public static String getNearestFunctionName(Node n) {
if (!n.isFunction()) {
return null;
}
String name = getName(n);
if (name != null) {
return name;
}
// Check for the form { 'x' : function() { }} and {x() {}}
Node parent = n.getParent();
switch (parent.getToken()) {
case MEMBER_FUNCTION_DEF:
case SETTER_DEF:
case GETTER_DEF:
case STRING_KEY:
// Return the name of the literal's key.
return parent.getString();
case NUMBER:
return getStringValue(parent);
default:
break;
}
return null;
}
public static Node getClassMembers(Node n) {
checkArgument(n.isClass());
return n.getLastChild();
}
@Nullable
public static Node getEs6ClassConstructorMemberFunctionDef(Node classNode) {
checkArgument(classNode.isClass(), classNode);
Node classMembers = checkNotNull(classNode.getLastChild(), classNode);
for (Node memberFunctionDef = classMembers.getFirstChild();
memberFunctionDef != null;
memberFunctionDef = memberFunctionDef.getNext()) {
if (isEs6ConstructorMemberFunctionDef(memberFunctionDef)) {
return memberFunctionDef;
}
}
return null;
}
/**
* Returns true if this is an immutable value.
*/
static boolean isImmutableValue(Node n) {
// TODO(johnlenz): rename this function. It is currently being used
// in two disjoint cases:
// 1) We only care about the result of the expression
// (in which case NOT here should return true)
// 2) We care that expression is a side-effect free and can't
// be side-effected by other expressions.
// This should only be used to say the value is immutable and
// hasSideEffects and canBeSideEffected should be used for the other case.
switch (n.getToken()) {
case STRING:
case NUMBER:
case NULL:
case TRUE:
case FALSE:
return true;
case CAST:
case NOT:
case VOID:
case NEG:
return isImmutableValue(n.getFirstChild());
case NAME:
String name = n.getString();
// We assume here that programs don't change the value of the keyword
// undefined to something other than the value undefined.
return "undefined".equals(name) || "Infinity".equals(name) || "NaN".equals(name);
case TEMPLATELIT:
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
if (child.isTemplateLitSub()) {
if (!isImmutableValue(child.getFirstChild())) {
return false;
}
}
}
return true;
default:
// TODO(yitingwang) There are probably other tokens that shouldn't get to the default branch
checkArgument(!n.isTemplateLitString());
break;
}
return false;
}
/**
* Returns true if the operator on this node is symmetric
*/
static boolean isSymmetricOperation(Node n) {
switch (n.getToken()) {
case EQ: // equal
case NE: // not equal
case SHEQ: // exactly equal
case SHNE: // exactly not equal
case MUL: // multiply, unlike add it only works on numbers
// or results NaN if any of the operators is not a number
return true;
default:
break;
}
return false;
}
/**
* Returns true if the operator on this node is relational.
* the returned set does not include the equalities.
*/
static boolean isRelationalOperation(Node n) {
switch (n.getToken()) {
case GT: // equal
case GE: // not equal
case LT: // exactly equal
case LE: // exactly not equal
return true;
default:
break;
}
return false;
}
/**
* Returns the inverse of an operator if it is invertible.
* ex. '>' ==> '<'
*/
static Token getInverseOperator(Token type) {
switch (type) {
case GT:
return Token.LT;
case LT:
return Token.GT;
case GE:
return Token.LE;
case LE:
return Token.GE;
default:
throw new IllegalArgumentException("Unexpected token: " + type);
}
}
/**
* Returns true if this is a literal value. We define a literal value
* as any node that evaluates to the same thing regardless of when or
* where it is evaluated. So /xyz/ and [3, 5] are literals, but
* the name a is not.
*
* Function literals do not meet this definition, because they
* lexically capture variables. For example, if you have
*
* function() { return a; }
*
* If it is evaluated in a different scope, then it
* captures a different variable. Even if the function did not read
* any captured variables directly, it would still fail this definition,
* because it affects the lifecycle of variables in the enclosing scope.
*
*
However, a function literal with respect to a particular scope is
* a literal.
*
* @param includeFunctions If true, all function expressions will be
* treated as literals.
*/
public static boolean isLiteralValue(Node n, boolean includeFunctions) {
switch (n.getToken()) {
case CAST:
return isLiteralValue(n.getFirstChild(), includeFunctions);
case ARRAYLIT:
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
if ((!child.isEmpty()) && !isLiteralValue(child, includeFunctions)) {
return false;
}
}
return true;
case REGEXP:
// Return true only if all descendants are const.
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
if (!isLiteralValue(child, includeFunctions)) {
return false;
}
}
return true;
case OBJECTLIT:
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
switch (child.getToken()) {
case MEMBER_FUNCTION_DEF:
case GETTER_DEF:
case SETTER_DEF:
// { methodName() {...} }
// { get propertyName() {...} }
// { set propertyName(value) {...} }
if (!includeFunctions) {
return false;
}
break;
case COMPUTED_PROP:
// { [key_expression]: value, ... }
// { [key_expression](args) {...}, ... }
// { get [key_expression]() {...}, ... }
// { set [key_expression](args) {...}, ... }
if (!isLiteralValue(child.getFirstChild(), includeFunctions)
|| !isLiteralValue(child.getLastChild(), includeFunctions)) {
return false;
}
break;
case SPREAD:
if (!isLiteralValue(child.getOnlyChild(), includeFunctions)) {
return false;
}
break;
case STRING_KEY:
// { key: value, ... }
// { "quoted_key": value, ... }
if (!isLiteralValue(child.getOnlyChild(), includeFunctions)) {
return false;
}
break;
default:
throw new IllegalArgumentException(
"Unexpected child of OBJECTLIT: " + child.toStringTree());
}
}
return true;
case FUNCTION:
return includeFunctions && !NodeUtil.isFunctionDeclaration(n);
case TEMPLATELIT:
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
if (child.isTemplateLitSub()) {
if (!isLiteralValue(child.getFirstChild(), includeFunctions)) {
return false;
}
}
}
return true;
default:
return isImmutableValue(n);
}
}
/**
* Returns true iff the value associated with the node is a JS string literal, a concatenation
* thereof or a ternary operator choosing between string literals.
*/
static boolean isSomeCompileTimeConstStringValue(Node node) {
// TODO(bangert): Support constants, using a Scope argument. See ConstParamCheck
if (node.isString() || (node.isTemplateLit() && node.hasOneChild())) {
return true;
} else if (node.isAdd()) {
checkState(node.hasTwoChildren(), node);
Node left = node.getFirstChild();
Node right = node.getLastChild();
return isSomeCompileTimeConstStringValue(left) && isSomeCompileTimeConstStringValue(right);
} else if (node.isHook()) {
// Ternary operator a ? b : c
Node left = node.getSecondChild();
Node right = node.getLastChild();
return isSomeCompileTimeConstStringValue(left) && isSomeCompileTimeConstStringValue(right);
}
return false;
}
/**
* Returns whether this a BLOCK node with no children.
*
* @param block The node.
*/
static boolean isEmptyBlock(Node block) {
if (!block.isBlock()) {
return false;
}
for (Node n = block.getFirstChild(); n != null; n = n.getNext()) {
if (!n.isEmpty()) {
return false;
}
}
return true;
}
static boolean isBinaryOperator(Node n) {
return isBinaryOperatorType(n.getToken());
}
/**
* An operator with two operands that does not assign a value to either.
* Once you cut through the layers of rules, these all parse similarly, taking
* LeftHandSideExpression operands on either side.
* Comma is not included, because it takes AssignmentExpression operands, making its syntax
* different.
*/
static boolean isBinaryOperatorType(Token type) {
switch (type) {
case OR:
case AND:
case BITOR:
case BITXOR:
case BITAND:
case EQ:
case NE:
case SHEQ:
case SHNE:
case LT:
case GT:
case LE:
case GE:
case INSTANCEOF:
case IN:
case LSH:
case RSH:
case URSH:
case ADD:
case SUB:
case MUL:
case DIV:
case MOD:
case EXPONENT:
return true;
default:
return false;
}
}
static boolean isUnaryOperator(Node n) {
return isUnaryOperatorType(n.getToken());
}
/**
* An operator taking only one operand.
* These all parse very similarly, taking LeftHandSideExpression operands.
*/
static boolean isUnaryOperatorType(Token type) {
switch (type) {
case DELPROP:
case VOID:
case TYPEOF:
case POS:
case NEG:
case BITNOT:
case NOT:
return true;
default:
return false;
}
}
static boolean isUpdateOperator(Node n) {
return isUpdateOperatorType(n.getToken());
}
static boolean isUpdateOperatorType(Token type) {
switch (type) {
case INC:
case DEC:
return true;
default:
return false;
}
}
static boolean isSimpleOperator(Node n) {
return isSimpleOperatorType(n.getToken());
}
/**
* A "simple" operator is one whose children are expressions,
* has no direct side-effects (unlike '+='), and has no
* conditional aspects (unlike '||').
*/
static boolean isSimpleOperatorType(Token type) {
switch (type) {
case ADD:
case BITAND:
case BITNOT:
case BITOR:
case BITXOR:
case COMMA:
case DIV:
case EQ:
case EXPONENT:
case GE:
case GETELEM:
case GETPROP:
case GT:
case IN:
case INSTANCEOF:
case LE:
case LSH:
case LT:
case MOD:
case MUL:
case NE:
case NOT:
case RSH:
case SHEQ:
case SHNE:
case SUB:
case TYPEOF:
case VOID:
case POS:
case NEG:
case URSH:
return true;
default:
return false;
}
}
/**
* True for aliases defined with @const, not for aliases defined with @constructor/@interface.
*/
static boolean isAliasedConstDefinition(Node lhs) {
JSDocInfo jsdoc = getBestJSDocInfo(lhs);
if (jsdoc == null && !lhs.isFromExterns()) {
return false;
}
if (jsdoc != null && !jsdoc.hasConstAnnotation()) {
return false;
}
Node rhs = getRValueOfLValue(lhs);
if (rhs == null || !rhs.isQualifiedName()) {
return false;
}
Node parent = lhs.getParent();
return (lhs.isName() && parent.isVar())
|| (lhs.isGetProp() && lhs.isQualifiedName()
&& parent.isAssign() && parent.getParent().isExprResult());
}
static boolean isTypedefDecl(Node n) {
if (n.isVar()
|| (n.isName() && n.getParent().isVar())
|| (n.isGetProp() && n.getParent().isExprResult())) {
JSDocInfo jsdoc = getBestJSDocInfo(n);
return jsdoc != null && jsdoc.hasTypedefType();
}
return false;
}
static boolean isEnumDecl(Node n) {
if (NodeUtil.isNameDeclaration(n)
|| (n.isName() && NodeUtil.isNameDeclaration(n.getParent()))
|| (n.isGetProp() && n.getParent().isAssign() && n.getGrandparent().isExprResult())
|| (n.isAssign() && n.getParent().isExprResult())) {
JSDocInfo jsdoc = getBestJSDocInfo(n);
return jsdoc != null && jsdoc.hasEnumParameterType();
}
return false;
}
/**
* Returns true iff this node defines a namespace, e.g.,
*
* /** @const * / var goog = {};
* /** @const * / var goog = goog || {};
* /** @const * / goog.math = goog.math || {};
*/
public static boolean isNamespaceDecl(Node n) {
JSDocInfo jsdoc = getBestJSDocInfo(n);
if (jsdoc != null && !jsdoc.getTypeNodes().isEmpty()) {
return false;
}
// In externs, we allow namespace definitions without @const.
// This is a worse design than always requiring @const, but it helps with
// namespaces that are defined in many places, such as gapi.
// Also, omitting @const in externs is not as confusing as in source code,
// because assigning an object literal in externs only makes sense when
// defining a namespace or enum.
boolean isMarkedConst = n.getParent().isConst() || (jsdoc != null && jsdoc.isConstant());
if (!n.isFromExterns() && !isMarkedConst) {
return false;
}
Node qnameNode;
Node initializer;
if (NodeUtil.isNameDeclaration(n.getParent())) {
qnameNode = n;
initializer = n.getFirstChild();
} else if (n.isExprResult()) {
Node expr = n.getFirstChild();
if (!expr.isAssign() || !expr.getFirstChild().isGetProp()) {
return false;
}
qnameNode = expr.getFirstChild();
initializer = expr.getLastChild();
} else if (n.isGetProp()) {
Node parent = n.getParent();
if (!parent.isAssign() || !parent.getParent().isExprResult()) {
return false;
}
qnameNode = n;
initializer = parent.getLastChild();
} else {
return false;
}
if (initializer == null || qnameNode == null) {
return false;
}
if (initializer.isObjectLit()) {
return true;
}
return initializer.isOr()
&& qnameNode.matchesQualifiedName(initializer.getFirstChild())
&& initializer.getLastChild().isObjectLit();
}
/** Determine if the given SCRIPT is a @typeSummary file, like an i.js file */
public static boolean isFromTypeSummary(Node n) {
checkArgument(n.isScript(), n);
JSDocInfo info = n.getJSDocInfo();
return info != null && info.isTypeSummary();
}
/**
* Creates an EXPR_RESULT.
*
* @param child The expression itself.
* @return Newly created EXPR node with the child as subexpression.
*/
static Node newExpr(Node child) {
return IR.exprResult(child).srcref(child);
}
/**
* Returns {@code true} if {@code node} might execute an `Iterable` iteration that has
* side-effects, {@code false} if there are definitely no such side-effects.
*
* This function only considers purity of the iteration. Other expressions within the {@code
* node} subtree may still have side-effects.
*
* @throws IllegalStateException if {@code node} is of a kind that does not trigger iteration. An
* explicit goal of this function is to record all the kinds of nodes that do.
*/
static boolean iteratesImpureIterable(Node node) {
Node parent = node.getParent();
final Node iterable;
switch (node.getToken()) {
case SPREAD:
switch (parent.getToken()) {
case OBJECTLIT:
return false; // Object spread does not iterate.
case NEW:
case ARRAYLIT:
case CALL:
iterable = node.getOnlyChild();
break;
default:
throw new IllegalStateException(
"Unexpected parent of SPREAD: " + parent.toStringTree());
}
break;
case YIELD:
if (!node.isYieldAll()) {
return false; // Regular `yield` does not iterate, only `yield*`.
}
iterable = node.getOnlyChild();
break;
case FOR_OF:
case FOR_AWAIT_OF:
iterable = node.getSecondChild();
break;
case REST:
switch (parent.getToken()) {
case OBJECT_PATTERN: // Object rest does not iterate.
case PARAM_LIST: // Rest arguments are flat at the call-site.
return false;
case ARRAY_PATTERN:
return true; // We assume the r-value to be an impure iterable.
default:
throw new IllegalStateException("Unexpected parent of REST: " + parent.toStringTree());
}
default:
throw new IllegalStateException(
"Expected a kind of node that may trigger iteration: " + node.toStringTree());
}
return !isPureIterable(iterable);
}
/**
* Returns {@code true} if {@code node} is guaranteed to be an `Iterable` that causes no
* side-effects during iteration, {@code false} otherwise.
*/
private static boolean isPureIterable(Node node) {
switch (node.getToken()) {
case ARRAYLIT:
case STRING:
case TEMPLATELIT:
return true; // These iterables are known to be pure.
default:
return false; // Anything else, including a non-iterable (e.g. `null`), would be impure.
}
}
/**
* @return Whether the call has a local result.
*/
static boolean callHasLocalResult(Node n) {
checkState(n.isCall() || n.isTaggedTemplateLit(), n);
return n.isLocalResultCall();
}
/**
* @return Whether the new has a local result.
*/
static boolean newHasLocalResult(Node n) {
checkState(n.isNew(), n);
return n.isOnlyModifiesThisCall();
}
static boolean allArgsUnescapedLocal(Node callOrNew) {
for (Node arg = callOrNew.getSecondChild(); arg != null; arg = arg.getNext()) {
if (!evaluatesToLocalValue(arg)) {
return false;
}
}
return true;
}
/**
* @return Whether the tree can be affected by side-effects or
* has side-effects.
*/
static boolean canBeSideEffected(Node n) {
return canBeSideEffected(n, ImmutableSet.of("undefined", "Infinity", "NaN"), null);
}
/**
* @param knownConstants A set of names known to be constant value at
* node 'n' (such as locals that are last written before n can execute).
* @return Whether the tree can be affected by side-effects or has side-effects.
*/
// TODO(nick): Get rid of the knownConstants argument in favor of using
// scope with InferConsts.
static boolean canBeSideEffected(Node n, Set knownConstants, @Nullable Scope scope) {
switch (n.getToken()) {
case YIELD:
case CALL:
case NEW:
// Function calls or constructor can reference changed values.
// TODO(johnlenz): Add some mechanism for determining that functions
// are unaffected by side effects.
return true;
case NAME:
// Non-constant names values may have been changed.
return !isConstantVar(n, scope) && !knownConstants.contains(n.getString());
// Properties on constant NAMEs can still be side-effected.
case GETPROP:
case GETELEM:
return true;
case FUNCTION:
// Function expression are not changed by side-effects,
// and function declarations are not part of expressions.
// TODO(bradfordcsmith): Do we need to add a case for CLASS here?
// This checkState currently does not exclude class methods.
checkState(!isFunctionDeclaration(n), n);
return false;
default:
break;
}
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
if (canBeSideEffected(c, knownConstants, scope)) {
return true;
}
}
return false;
}
/**
* The comma operator has the lowest precedence, 0, followed by the assignment operators
* ({@code =}, {@code &=}, {@code +=}, etc.) which have precedence of 1, and so on.
*
* See
* https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence
*/
public static int precedence(Token type) {
switch (type) {
case COMMA: return 0;
case ASSIGN_BITOR:
case ASSIGN_BITXOR:
case ASSIGN_BITAND:
case ASSIGN_LSH:
case ASSIGN_RSH:
case ASSIGN_URSH:
case ASSIGN_ADD:
case ASSIGN_SUB:
case ASSIGN_MUL:
case ASSIGN_EXPONENT:
case ASSIGN_DIV:
case ASSIGN_MOD:
case ASSIGN: return 1;
case YIELD: return 2;
case HOOK: return 3; // ?: operator
case OR: return 4;
case AND: return 5;
case BITOR: return 6;
case BITXOR: return 7;
case BITAND: return 8;
case EQ:
case NE:
case SHEQ:
case SHNE: return 9;
case LT:
case GT:
case LE:
case GE:
case INSTANCEOF:
case IN: return 10;
case LSH:
case RSH:
case URSH: return 11;
case SUB:
case ADD: return 12;
case MUL:
case MOD:
case DIV:
return 13;
case EXPONENT:
return 14;
case AWAIT:
case NEW:
case DELPROP:
case TYPEOF:
case VOID:
case NOT:
case BITNOT:
case POS:
case NEG:
return 15; // Unary operators
case INC:
case DEC:
return 16; // Update operators
case CALL:
case GETELEM:
case GETPROP:
case NEW_TARGET:
// Data values
case ARRAYLIT:
case ARRAY_PATTERN:
case DEFAULT_VALUE:
case DESTRUCTURING_LHS:
case EMPTY: // TODO(johnlenz): remove this.
case FALSE:
case FUNCTION:
case CLASS:
case INTERFACE:
case NAME:
case NULL:
case NUMBER:
case OBJECTLIT:
case OBJECT_PATTERN:
case REGEXP:
case REST:
case SPREAD:
case STRING:
case STRING_KEY:
case MEMBER_VARIABLE_DEF:
case INDEX_SIGNATURE:
case CALL_SIGNATURE:
case THIS:
case SUPER:
case TRUE:
case TAGGED_TEMPLATELIT:
case TEMPLATELIT:
case DYNAMIC_IMPORT:
// Tokens from the type declaration AST
case UNION_TYPE:
return 17;
case FUNCTION_TYPE:
return 18;
case ARRAY_TYPE:
case PARAMETERIZED_TYPE:
return 19;
case STRING_TYPE:
case NUMBER_TYPE:
case BOOLEAN_TYPE:
case ANY_TYPE:
case RECORD_TYPE:
case NULLABLE_TYPE:
case NAMED_TYPE:
case UNDEFINED_TYPE:
case GENERIC_TYPE:
return 20;
case CAST:
return 21;
default:
checkArgument(type != Token.TEMPLATELIT_STRING);
throw new IllegalStateException("Unknown precedence for " + type);
}
}
public static boolean isUndefined(Node n) {
switch (n.getToken()) {
case VOID:
return true;
case NAME:
return n.getString().equals("undefined");
default:
break;
}
return false;
}
public static boolean isNullOrUndefined(Node n) {
return n.isNull() || isUndefined(n);
}
static boolean isImmutableResult(Node n) {
return allResultsMatch(n, NodeUtil::isImmutableValue);
}
/**
* Apply the supplied predicate against
* all possible result Nodes of the expression.
*/
static boolean allResultsMatch(Node n, Predicate p) {
switch (n.getToken()) {
case CAST:
return allResultsMatch(n.getFirstChild(), p);
case ASSIGN:
case COMMA:
return allResultsMatch(n.getLastChild(), p);
case AND:
case OR:
return allResultsMatch(n.getFirstChild(), p)
&& allResultsMatch(n.getLastChild(), p);
case HOOK:
return allResultsMatch(n.getSecondChild(), p)
&& allResultsMatch(n.getLastChild(), p);
default:
return p.apply(n);
}
}
/** @see #getKnownValueType(Node) */
public enum ValueType {
UNDETERMINED,
NULL,
VOID,
NUMBER,
STRING,
BOOLEAN,
OBJECT
}
/**
* Apply the supplied predicate against
* all possible result Nodes of the expression.
*/
public static ValueType getKnownValueType(Node n) {
switch (n.getToken()) {
case CAST:
return getKnownValueType(n.getFirstChild());
case ASSIGN:
case COMMA:
return getKnownValueType(n.getLastChild());
case AND:
case OR:
return and(
getKnownValueType(n.getFirstChild()),
getKnownValueType(n.getLastChild()));
case HOOK:
return and(
getKnownValueType(n.getSecondChild()),
getKnownValueType(n.getLastChild()));
case ADD: {
ValueType last = getKnownValueType(n.getLastChild());
if (last == ValueType.STRING) {
return ValueType.STRING;
}
ValueType first = getKnownValueType(n.getFirstChild());
if (first == ValueType.STRING) {
return ValueType.STRING;
}
// There are some pretty weird cases for object types:
// {} + [] === "0"
// [] + {} ==== "[object Object]"
if (first == ValueType.OBJECT || last == ValueType.OBJECT) {
return ValueType.UNDETERMINED;
}
if (!mayBeString(first) && !mayBeString(last)) {
// ADD used with compilations of null, undefined, boolean and number always result
// in numbers.
return ValueType.NUMBER;
}
// There are some pretty weird cases for object types:
// {} + [] === "0"
// [] + {} ==== "[object Object]"
return ValueType.UNDETERMINED;
}
case ASSIGN_ADD: {
ValueType last = getKnownValueType(n.getLastChild());
if (last == ValueType.STRING) {
return ValueType.STRING;
}
return ValueType.UNDETERMINED;
}
case NAME:
String name = n.getString();
if (name.equals("undefined")) {
return ValueType.VOID;
}
if (name.equals("NaN")) {
return ValueType.NUMBER;
}
if (name.equals("Infinity")) {
return ValueType.NUMBER;
}
return ValueType.UNDETERMINED;
case ASSIGN_BITOR:
case ASSIGN_BITXOR:
case ASSIGN_BITAND:
case ASSIGN_LSH:
case ASSIGN_RSH:
case ASSIGN_URSH:
case ASSIGN_SUB:
case ASSIGN_MUL:
case ASSIGN_EXPONENT:
case ASSIGN_DIV:
case ASSIGN_MOD:
case BITNOT:
case BITOR:
case BITXOR:
case BITAND:
case LSH:
case RSH:
case URSH:
case SUB:
case MUL:
case MOD:
case DIV:
case EXPONENT:
case INC:
case DEC:
case POS:
case NEG:
case NUMBER:
return ValueType.NUMBER;
// Primitives
case TRUE:
case FALSE:
// Comparisons
case EQ:
case NE:
case SHEQ:
case SHNE:
case LT:
case GT:
case LE:
case GE:
// Queries
case IN:
case INSTANCEOF:
// Inversion
case NOT:
// delete operator returns a boolean.
case DELPROP:
return ValueType.BOOLEAN;
case TYPEOF:
case STRING:
case TEMPLATELIT:
return ValueType.STRING;
case NULL:
return ValueType.NULL;
case VOID:
return ValueType.VOID;
case FUNCTION:
case NEW:
case ARRAYLIT:
case OBJECTLIT:
case REGEXP:
return ValueType.OBJECT;
default:
checkArgument(!n.isTemplateLitString());
return ValueType.UNDETERMINED;
}
}
static ValueType and(ValueType a, ValueType b) {
return (a == b) ? a : ValueType.UNDETERMINED;
}
/**
* Returns true if the result of node evaluation is always a number
*/
public static boolean isNumericResult(Node n) {
return getKnownValueType(n) == ValueType.NUMBER;
}
/**
* @return Whether the result of node evaluation is always a boolean
*/
public static boolean isBooleanResult(Node n) {
return getKnownValueType(n) == ValueType.BOOLEAN;
}
/**
* @return Whether the result of node evaluation is always a string
*/
public static boolean isStringResult(Node n) {
return getKnownValueType(n) == ValueType.STRING;
}
/**
* @return Whether the result of node evaluation is always an object
*/
public static boolean isObjectResult(Node n) {
return getKnownValueType(n) == ValueType.OBJECT;
}
static boolean mayBeString(Node n) {
return mayBeString(n, false);
}
/**
* Return if the node is possibly a string.
*
* @param n The node.
* @param useType If true and the node has a primitive type, return true if that type is string
* and false otherwise.
* @return Whether the results is possibly a string.
*/
static boolean mayBeString(Node n, boolean useType) {
if (useType) {
JSType type = n.getJSType();
if (type != null) {
if (type.isStringValueType()) {
return true;
} else if (type.isNumberValueType() || type.isBooleanValueType() || type.isNullType()
|| type.isVoidType()) {
return false;
}
}
}
return mayBeString(getKnownValueType(n));
}
/**
* @return Whether the results is possibly a string, this includes Objects which may implicitly
* be converted to a string.
*/
static boolean mayBeString(ValueType type) {
switch (type) {
case BOOLEAN:
case NULL:
case NUMBER:
case VOID:
return false;
case OBJECT:
case STRING:
case UNDETERMINED:
return true;
default:
throw new IllegalStateException("unexpected");
}
}
static boolean mayBeObject(Node n) {
return mayBeObject(getKnownValueType(n));
}
static boolean mayBeObject(ValueType type) {
switch (type) {
case BOOLEAN:
case NULL:
case NUMBER:
case STRING:
case VOID:
return false;
case OBJECT:
case UNDETERMINED:
return true;
default:
throw new IllegalStateException("unexpected");
}
}
/**
* Returns true if the operator is associative.
* e.g. (a * b) * c = a * (b * c)
* Note: "+" is not associative because it is also the concatenation
* for strings. e.g. "a" + (1 + 2) is not "a" + 1 + 2
*/
static boolean isAssociative(Token type) {
switch (type) {
case MUL:
case AND:
case OR:
case BITOR:
case BITXOR:
case BITAND:
return true;
default:
return false;
}
}
/**
* Returns true if the operator is commutative.
* e.g. (a * b) * c = c * (b * a)
* Note 1: "+" is not commutative because it is also the concatenation
* for strings. e.g. "a" + (1 + 2) is not "a" + 1 + 2
* Note 2: only operations on literals and pure functions are commutative.
*/
static boolean isCommutative(Token type) {
switch (type) {
case MUL:
case BITOR:
case BITXOR:
case BITAND:
return true;
default:
return false;
}
}
public static boolean isAssignmentOp(Node n) {
switch (n.getToken()) {
case ASSIGN:
case ASSIGN_BITOR:
case ASSIGN_BITXOR:
case ASSIGN_BITAND:
case ASSIGN_LSH:
case ASSIGN_RSH:
case ASSIGN_URSH:
case ASSIGN_ADD:
case ASSIGN_SUB:
case ASSIGN_MUL:
case ASSIGN_EXPONENT:
case ASSIGN_DIV:
case ASSIGN_MOD:
return true;
default:
break;
}
return false;
}
public static boolean isCompoundAssignmentOp(Node n) {
return isAssignmentOp(n) && !n.isAssign();
}
static Token getOpFromAssignmentOp(Node n) {
switch (n.getToken()) {
case ASSIGN_BITOR:
return Token.BITOR;
case ASSIGN_BITXOR:
return Token.BITXOR;
case ASSIGN_BITAND:
return Token.BITAND;
case ASSIGN_LSH:
return Token.LSH;
case ASSIGN_RSH:
return Token.RSH;
case ASSIGN_URSH:
return Token.URSH;
case ASSIGN_ADD:
return Token.ADD;
case ASSIGN_SUB:
return Token.SUB;
case ASSIGN_MUL:
return Token.MUL;
case ASSIGN_EXPONENT:
return Token.EXPONENT;
case ASSIGN_DIV:
return Token.DIV;
case ASSIGN_MOD:
return Token.MOD;
default:
break;
}
throw new IllegalArgumentException("Not an assignment op:" + n);
}
static Token getAssignOpFromOp(Node n) {
switch (n.getToken()) {
case BITOR:
return Token.ASSIGN_BITOR;
case BITXOR:
return Token.ASSIGN_BITXOR;
case BITAND:
return Token.ASSIGN_BITAND;
case LSH:
return Token.ASSIGN_LSH;
case RSH:
return Token.ASSIGN_RSH;
case URSH:
return Token.ASSIGN_URSH;
case ADD:
return Token.ASSIGN_ADD;
case SUB:
return Token.ASSIGN_SUB;
case MUL:
return Token.ASSIGN_MUL;
case EXPONENT:
return Token.ASSIGN_EXPONENT;
case DIV:
return Token.ASSIGN_DIV;
case MOD:
return Token.ASSIGN_MOD;
default:
throw new IllegalStateException("Unexpected operator: " + n);
}
}
static boolean hasCorrespondingAssignmentOp(Node n) {
switch (n.getToken()) {
case BITOR:
case BITXOR:
case BITAND:
case LSH:
case RSH:
case URSH:
case ADD:
case SUB:
case MUL:
case DIV:
case MOD:
return true;
default:
return false;
}
}
/**
* Determines if the given node contains a function statement or function
* expression.
*/
static boolean containsFunction(Node n) {
return containsType(n, Token.FUNCTION);
}
/** Gets the closest ancestor to the given node of the provided type. */
public static Node getEnclosingType(Node n, final Token type) {
return getEnclosingNode(
n,
new Predicate() {
@Override
public boolean apply(Node n) {
return n.getToken() == type;
}
});
}
/** Finds the class member function containing the given node. */
static Node getEnclosingClassMemberFunction(Node n) {
return getEnclosingType(n, Token.MEMBER_FUNCTION_DEF);
}
/** Finds the class containing the given node. */
public static Node getEnclosingClass(Node n) {
return getEnclosingType(n, Token.CLASS);
}
/** Finds the function containing the given node. */
public static Node getEnclosingFunction(Node n) {
return getEnclosingType(n, Token.FUNCTION);
}
/** Finds the script containing the given node. */
public static Node getEnclosingScript(Node n) {
return getEnclosingType(n, Token.SCRIPT);
}
/** Finds the block containing the given node. */
public static Node getEnclosingBlock(Node n) {
return getEnclosingType(n, Token.BLOCK);
}
public static Node getEnclosingBlockScopeRoot(Node n) {
return getEnclosingNode(n, NodeUtil::createsBlockScope);
}
public static Node getEnclosingScopeRoot(Node n) {
return getEnclosingNode(n, NodeUtil::createsScope);
}
public static boolean isInFunction(Node n) {
return getEnclosingFunction(n) != null;
}
public static Node getEnclosingStatement(Node n) {
return getEnclosingNode(n, NodeUtil::isStatement);
}
public static Node getEnclosingNode(Node n, Predicate pred) {
Node curr = n;
while (curr != null && !pred.apply(curr)) {
curr = curr.getParent();
}
return curr;
}
/**
* @return The first property in the objlit or class members, that matches the key.
*/
@Nullable
static Node getFirstPropMatchingKey(Node n, String keyName) {
checkState(n.isObjectLit() || n.isClassMembers());
for (Node keyNode : n.children()) {
if ((keyNode.isStringKey() || keyNode.isMemberFunctionDef())
&& keyNode.getString().equals(keyName)) {
return keyNode.getFirstChild();
}
}
return null;
}
/** @return The first getter in the class members that matches the key. */
@Nullable
static Node getFirstGetterMatchingKey(Node n, String keyName) {
checkState(n.isClassMembers() || n.isObjectLit(), n);
for (Node keyNode : n.children()) {
if (keyNode.isGetterDef() && keyNode.getString().equals(keyName)) {
return keyNode;
}
}
return null;
}
/** @return The first setter in the class members that matches the key. */
@Nullable
static Node getFirstSetterMatchingKey(Node n, String keyName) {
checkState(n.isClassMembers() || n.isObjectLit(), n);
for (Node keyNode : n.children()) {
if (keyNode.isSetterDef() && keyNode.getString().equals(keyName)) {
return keyNode;
}
}
return null;
}
/** @return The first computed property in the objlit whose key matches {@code key}. */
@Nullable
static Node getFirstComputedPropMatchingKey(Node objlit, Node key) {
checkState(objlit.isObjectLit());
for (Node child : objlit.children()) {
if (child.isComputedProp() && child.getFirstChild().isEquivalentTo(key)) {
return child.getLastChild();
}
}
return null;
}
/**
* Returns true if the shallow scope contains references to 'this' keyword
*/
static boolean referencesThis(Node n) {
if (n.isFunction()) {
return referencesThis(NodeUtil.getFunctionParameters(n))
|| referencesThis(NodeUtil.getFunctionBody(n));
} else {
return has(n, Node::isThis, MATCH_ANYTHING_BUT_NON_ARROW_FUNCTION);
}
}
/**
* Returns true if the current scope contains references to the 'super' keyword.
* Note that if there are classes declared inside the current class, super calls which
* reference those classes are not reported.
*/
static boolean referencesSuper(Node n) {
Node curr = n.getFirstChild();
while (curr != null) {
if (containsType(curr, Token.SUPER, node -> !node.isClass())) {
return true;
}
curr = curr.getNext();
}
return false;
}
/**
* Is this a GETPROP or GETELEM node?
*/
public static boolean isGet(Node n) {
return n.isGetProp() || n.isGetElem();
}
/**
* Is this node the name of a block-scoped declaration?
* Checks for let, const, class, or block-scoped function declarations.
*
* @param n The node
* @return True if {@code n} is the NAME of a block-scoped declaration.
*/
static boolean isBlockScopedDeclaration(Node n) {
if (n.isName()) {
switch (n.getParent().getToken()) {
case LET:
case CONST:
case CATCH:
return true;
case CLASS:
return n.getParent().getFirstChild() == n;
case FUNCTION:
return isBlockScopedFunctionDeclaration(n.getParent());
default:
break;
}
}
return false;
}
/**
* Is this node a name declaration?
*
* @param n The node
* @return True if {@code n} is VAR, LET or CONST
*/
public static boolean isNameDeclaration(Node n) {
return n != null && (n.isVar() || n.isLet() || n.isConst());
}
/**
* @param n The node
* @return True if {@code n} is a VAR, LET or CONST that contains a
* destructuring pattern.
*/
static boolean isDestructuringDeclaration(Node n) {
if (isNameDeclaration(n)) {
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
if (c.isDestructuringLhs()) {
return true;
}
}
}
return false;
}
/**
* For an assignment or variable declaration get the assigned value.
* @return The value node representing the new value.
*/
public static Node getAssignedValue(Node n) {
checkState(n.isName() || n.isGetProp(), n);
Node parent = n.getParent();
if (NodeUtil.isNameDeclaration(parent)) {
return n.getFirstChild();
} else if (parent.isAssign() && parent.getFirstChild() == n) {
return n.getNext();
} else {
return null;
}
}
/**
* Is this node an assignment expression statement?
*
* @param n The node
* @return True if {@code n} is EXPR_RESULT and {@code n}'s
* first child is ASSIGN
*/
static boolean isExprAssign(Node n) {
return n.isExprResult()
&& n.getFirstChild().isAssign();
}
/**
* Is this node a call expression statement?
*
* @param n The node
* @return True if {@code n} is EXPR_RESULT and {@code n}'s
* first child is CALL
*/
public static boolean isExprCall(Node n) {
return n.isExprResult()
&& n.getFirstChild().isCall();
}
static boolean isNonArrowFunction(Node n) {
return n.isFunction() && !n.isArrowFunction();
}
public static boolean isEnhancedFor(Node n) {
return n.isForOf() || n.isForAwaitOf() || n.isForIn();
}
public static boolean isAnyFor(Node n) {
return n.isVanillaFor() || n.isForIn() || n.isForOf() || n.isForAwaitOf();
}
/**
* Determines whether the given node is a FOR, DO, or WHILE node.
*/
static boolean isLoopStructure(Node n) {
switch (n.getToken()) {
case FOR:
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
case DO:
case WHILE:
return true;
default:
return false;
}
}
/**
* @param n The node to inspect.
* @return If the node, is a FOR, WHILE, or DO, it returns the node for
* the code BLOCK, null otherwise.
*/
static Node getLoopCodeBlock(Node n) {
switch (n.getToken()) {
case FOR:
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
case WHILE:
return n.getLastChild();
case DO:
return n.getFirstChild();
default:
return null;
}
}
/**
* @return Whether the specified node has a loop parent that
* is within the current scope.
*/
static boolean isWithinLoop(Node n) {
for (Node parent : n.getAncestors()) {
if (NodeUtil.isLoopStructure(parent)) {
return true;
}
if (parent.isFunction()) {
break;
}
}
return false;
}
/**
* Determines whether the given node is a FOR, DO, WHILE, WITH, or IF node.
*/
public static boolean isControlStructure(Node n) {
switch (n.getToken()) {
case FOR:
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
case DO:
case WHILE:
case WITH:
case IF:
case LABEL:
case TRY:
case CATCH:
case SWITCH:
case CASE:
case DEFAULT_CASE:
return true;
default:
return false;
}
}
/**
* Determines whether the given node is code node for FOR, DO,
* WHILE, WITH, or IF node.
*/
static boolean isControlStructureCodeBlock(Node parent, Node n) {
switch (parent.getToken()) {
case DO:
return parent.getFirstChild() == n;
case TRY:
return parent.getFirstChild() == n || parent.getLastChild() == n;
case FOR:
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
case WHILE:
case LABEL:
case WITH:
case CATCH:
return parent.getLastChild() == n;
case IF:
case SWITCH:
case CASE:
return parent.getFirstChild() != n;
case DEFAULT_CASE:
return true;
default:
checkState(isControlStructure(parent), parent);
return false;
}
}
/**
* Gets the condition of an ON_TRUE / ON_FALSE CFG edge.
* @param n a node with an outgoing conditional CFG edge
* @return the condition node or null if the condition is not obviously a node
*/
static Node getConditionExpression(Node n) {
switch (n.getToken()) {
case IF:
case WHILE:
return n.getFirstChild();
case DO:
return n.getLastChild();
case FOR:
return n.getSecondChild();
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
case CASE:
return null;
default:
break;
}
throw new IllegalArgumentException(n + " does not have a condition.");
}
/**
* @return Whether the node is of a type that contain other statements.
*/
public static boolean isStatementBlock(Node n) {
return n.isRoot() || n.isScript() || n.isBlock() || n.isModuleBody();
}
/**
* A block scope is created by a non-synthetic block node, a for loop node,
* or a for-of loop node.
*
* Note: for functions, we use two separate scopes for parameters and
* declarations in the body. We need to make sure default parameters cannot
* reference var / function declarations in the body.
*
* @return Whether the node creates a block scope.
*/
static boolean createsBlockScope(Node n) {
switch (n.getToken()) {
case BLOCK:
Node parent = n.getParent();
// Don't create block scope for switch cases or catch blocks.
return parent != null && !isSwitchCase(parent) && !parent.isCatch();
case FOR:
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
case SWITCH:
case CLASS:
return true;
default:
return false;
}
}
static boolean createsScope(Node n) {
return createsBlockScope(n) || n.isFunction() || n.isModuleBody()
// The ROOT nodes that are the root of the externs tree or main JS tree do not
// create scopes. The parent of those two, which is the root of the entire AST and
// therefore has no parent, is the only ROOT node that creates a scope.
|| (n.isRoot() && n.getParent() == null);
}
private static final Set DEFINITE_CFG_ROOTS =
EnumSet.of(Token.FUNCTION, Token.SCRIPT, Token.MODULE_BODY, Token.ROOT);
static boolean isValidCfgRoot(Node n) {
return DEFINITE_CFG_ROOTS.contains(n.getToken());
}
/**
* @return Whether the node is used as a statement.
*/
public static boolean isStatement(Node n) {
return !n.isModuleBody() && isStatementParent(n.getParent());
}
private static final Set IS_STATEMENT_PARENT =
EnumSet.of(
Token.SCRIPT,
Token.MODULE_BODY,
Token.BLOCK,
Token.LABEL,
Token.NAMESPACE_ELEMENTS,
Token.INTERFACE_MEMBERS);
public static boolean isStatementParent(Node parent) {
// It is not possible to determine definitely if a node is a statement
// or not if it is not part of the AST. A FUNCTION node can be
// either part of an expression or a statement.
return IS_STATEMENT_PARENT.contains(parent.getToken());
}
private static boolean isDeclarationParent(Node parent) {
switch (parent.getToken()) {
case DECLARE:
case EXPORT:
return true;
default:
return isStatementParent(parent);
}
}
/** Whether the node is part of a switch statement. */
static boolean isSwitchCase(Node n) {
return n.isCase() || n.isDefaultCase();
}
/**
* @return Whether the node is a reference to a variable, function, class or
* function parameter (not a label or an empty function expression name).
*/
static boolean isReferenceName(Node n) {
return n.isName() && !n.getString().isEmpty();
}
/**
* Returns whether the given name in an import or export spec is not defined within the module,
* but is an exported name from this or another module.
*
* Examples include `nonlocal` in:
*
*
* - export {a as nonlocal};
*
- import {nonlocal} from './foo.js';
*
- import {nonlocal as a} from './foo.js';
*
- export {nonlocal as a} from './foo.js';
*
- export {a as nonlocal} from './foo.js';
*
*
* @param n a NAME node.
*/
static boolean isNonlocalModuleExportName(Node n) {
checkArgument(n.isName(), n);
Node parent = n.getParent();
if (parent.isImportSpec() && n.isFirstChildOf(parent)) {
// import {nonlocal as x} from './foo.js'
return true;
} else if (parent.isExportSpec()) {
if (n.isFirstChildOf(parent)) {
// export {nonlocal as b} from './foo.js';
return isExportFrom(parent.getGrandparent());
} else {
// export {local as nonlocal};
return true;
}
}
return false;
}
/** Whether the child node is the FINALLY block of a try. */
static boolean isTryFinallyNode(Node parent, Node child) {
return parent.isTry() && parent.hasXChildren(3)
&& child == parent.getLastChild();
}
/** Whether the node is a CATCH container BLOCK. */
static boolean isTryCatchNodeContainer(Node n) {
Node parent = n.getParent();
return parent.isTry()
&& parent.getSecondChild() == n;
}
// TODO(tbreisacher): Add a method for detecting nodes injected as runtime libraries.
static boolean isInSyntheticScript(Node n) {
return n.getSourceFileName() != null && n.getSourceFileName().startsWith(" [synthetic:");
}
/**
* Permanently delete the given node from the AST, as well as report
* the related AST changes/deletions to the given compiler.
*/
public static void deleteNode(Node n, AbstractCompiler compiler) {
Node parent = n.getParent();
NodeUtil.markFunctionsDeleted(n, compiler);
n.detach();
compiler.reportChangeToEnclosingScope(parent);
}
/**
* Permanently delete the given call from the AST while maintaining a valid node structure, as
* well as report the related AST changes to the given compiler. In some cases, this is done by
* deleting the parent from the AST and is come cases expression is replaced by {@code
* undefined}.
*/
public static void deleteFunctionCall(Node n, AbstractCompiler compiler) {
checkState(n.isCall());
Node parent = n.getParent();
if (parent.isExprResult()) {
Node grandParent = parent.getParent();
grandParent.removeChild(parent);
parent = grandParent;
} else {
// Seems like part of more complex expression, fallback to replacing with no-op.
parent.replaceChild(n, newUndefinedNode(n));
}
NodeUtil.markFunctionsDeleted(n, compiler);
compiler.reportChangeToEnclosingScope(parent);
}
/**
* Permanently delete all the children of the given node, including reporting changes.
*/
public static void deleteChildren(Node n, AbstractCompiler compiler) {
while (n.hasChildren()) {
deleteNode(n.getFirstChild(), compiler);
}
}
/**
* Safely remove children while maintaining a valid node structure.
* In some cases, this is done by removing the parent from the AST as well.
*/
public static void removeChild(Node parent, Node node) {
if (isTryFinallyNode(parent, node)) {
if (NodeUtil.hasCatchHandler(getCatchBlock(parent))) {
// A finally can only be removed if there is a catch.
parent.removeChild(node);
} else {
// Otherwise, only its children can be removed.
node.detachChildren();
}
} else if (node.isCatch()) {
// The CATCH can can only be removed if there is a finally clause.
Node tryNode = node.getGrandparent();
checkState(NodeUtil.hasFinally(tryNode));
node.detach();
} else if (isTryCatchNodeContainer(node)) {
// The container node itself can't be removed, but the contained CATCH
// can if there is a 'finally' clause
Node tryNode = node.getParent();
checkState(NodeUtil.hasFinally(tryNode));
node.detachChildren();
} else if (node.isBlock()) {
// Simply empty the block. This maintains source location and
// "synthetic"-ness.
node.detachChildren();
} else if (isStatementBlock(parent)
|| isSwitchCase(node)
|| node.isMemberFunctionDef()) {
// A statement in a block or a member function can simply be removed
parent.removeChild(node);
} else if (isNameDeclaration(parent) || parent.isExprResult()) {
if (parent.hasMoreThanOneChild()) {
parent.removeChild(node);
} else {
// Remove the node from the parent, so it can be reused.
parent.removeChild(node);
// This would leave an empty VAR, remove the VAR itself.
removeChild(parent.getParent(), parent);
}
} else if (parent.isLabel()
&& node == parent.getLastChild()) {
// Remove the node from the parent, so it can be reused.
parent.removeChild(node);
// A LABEL without children can not be referred to, remove it.
removeChild(parent.getParent(), parent);
} else if (parent.isVanillaFor()) {
// Only Token.FOR can have an Token.EMPTY other control structure
// need something for the condition. Others need to be replaced
// or the structure removed.
parent.replaceChild(node, IR.empty());
} else if (parent.isObjectPattern()) {
// Remove the name from the object pattern
parent.removeChild(node);
} else if (parent.isArrayPattern()) {
if (node == parent.getLastChild()) {
parent.removeChild(node);
} else {
parent.replaceChild(node, IR.empty());
}
} else if (parent.isDestructuringLhs()) {
// Destructuring is empty so we should remove the node
parent.removeChild(node);
if (parent.getParent().hasChildren()) {
// removing the destructuring could leave an empty variable declaration node, so we would
// want to remove it from the AST
removeChild(parent.getParent(), parent);
}
} else if (parent.isRest()) {
// Rest params can only ever have one child node
parent.detach();
} else if (parent.isParamList()) {
parent.removeChild(node);
} else if (parent.isImport()) {
// An import node must always have three child nodes. Only the first can be safely removed.
if (node == parent.getFirstChild()) {
parent.replaceChild(node, IR.empty());
} else {
throw new IllegalStateException("Invalid attempt to remove: " + node + " from " + parent);
}
} else {
throw new IllegalStateException("Invalid attempt to remove node: " + node + " of " + parent);
}
}
/**
* Replace the child of a var/let/const declaration (usually a name) with a new statement.
* Preserves the order of side effects for all the other declaration children.
*
* @param declChild The name node to be replaced.
* @param newStatement The statement to replace with.
*/
public static void replaceDeclarationChild(Node declChild, Node newStatement) {
checkArgument(isNameDeclaration(declChild.getParent()));
checkArgument(null == newStatement.getParent());
Node decl = declChild.getParent();
Node declParent = decl.getParent();
if (decl.hasOneChild()) {
declParent.replaceChild(decl, newStatement);
} else if (declChild.getNext() == null) {
decl.removeChild(declChild);
declParent.addChildAfter(newStatement, decl);
} else if (declChild.getPrevious() == null) {
decl.removeChild(declChild);
declParent.addChildBefore(newStatement, decl);
} else {
checkState(decl.hasMoreThanOneChild());
Node newDecl = new Node(decl.getToken()).srcref(decl);
for (Node after = declChild.getNext(), next; after != null; after = next) {
next = after.getNext();
newDecl.addChildToBack(after.detach());
}
decl.removeChild(declChild);
declParent.addChildAfter(newStatement, decl);
declParent.addChildAfter(newDecl, newStatement);
}
}
/**
* Add a finally block if one does not exist.
*/
static void maybeAddFinally(Node tryNode) {
checkState(tryNode.isTry());
if (!NodeUtil.hasFinally(tryNode)) {
tryNode.addChildToBack(IR.block().srcref(tryNode));
}
}
/**
* Merge a block with its parent block.
* @return Whether the block was removed.
*/
public static boolean tryMergeBlock(Node block, boolean alwaysMerge) {
checkState(block.isBlock());
Node parent = block.getParent();
boolean canMerge = alwaysMerge || canMergeBlock(block);
// Try to remove the block if its parent is a block/script or if its
// parent is label and it has exactly one child.
if (isStatementBlock(parent) && canMerge) {
Node previous = block;
while (block.hasChildren()) {
Node child = block.removeFirstChild();
parent.addChildAfter(child, previous);
previous = child;
}
parent.removeChild(block);
return true;
} else {
return false;
}
}
/**
* A check inside a block to see if there are const, let, class, or function declarations
* to be safe and not hoist them into the upper block.
* @return Whether the block can be removed
*/
public static boolean canMergeBlock(Node block) {
for (Node c = block.getFirstChild(); c != null; c = c.getNext()) {
switch (c.getToken()) {
case LABEL:
if (canMergeBlock(c)){
continue;
} else {
return false;
}
case CONST:
case LET:
case CLASS:
case FUNCTION:
return false;
default:
continue;
}
}
return true;
}
/**
* @param node A node
* @return Whether the call is a NEW or CALL node.
*/
public static boolean isCallOrNew(Node node) {
return node.isCall() || node.isNew();
}
/**
* Return a BLOCK node for the given FUNCTION node.
*/
public static Node getFunctionBody(Node fn) {
checkArgument(fn.isFunction(), fn);
return fn.getLastChild();
}
/**
* Is the node a var, const, let, function, or class declaration?
* See {@link #isFunctionDeclaration}, {@link #isClassDeclaration}, and {@link #isNameDeclaration}
*/
static boolean isDeclaration(Node n) {
return isNameDeclaration(n) || isFunctionDeclaration(n) || isClassDeclaration(n);
}
/**
* Is this node a function declaration? A function declaration is a function
* that has a name that is added to the current scope (i.e. a function that
* is not part of a expression; see {@link #isFunctionExpression}).
*/
public static boolean isFunctionDeclaration(Node n) {
// Note: There is currently one case where an unnamed function has a declaration parent.
// `export default function() {...}`
// In this case we consider the function to be an expression.
return n.isFunction() && isDeclarationParent(n.getParent()) && isNamedFunction(n);
}
/**
* Is this node a class or object literal member function?
*
* examples:
*
*
* class C {
* f() {}
* get x() { return this.x_; }
* set x(v) { this.x_ = v; }
* [someExpr]() {}
* }
* obj = {
* f() {}
* get x() { return this.x_; }
* set x(v) { this.x_ = v; }
* [someExpr]() {}
* }
*
*/
public static boolean isMethodDeclaration(Node n) {
if (n.isFunction()) {
Node parent = n.getParent();
switch (parent.getToken()) {
case GETTER_DEF:
case SETTER_DEF:
case MEMBER_FUNCTION_DEF:
// `({ get x() {} })`
// `({ set x(v) {} })`
// `({ f() {} })`
return true;
case COMPUTED_PROP:
// `({ [expression]() {} })`
// `({ get [expression]() {} })`
// `({ set [expression](x) {} })`
// (but not `({ [expression]: function() {} })`
// The first child is the expression, and could possibly be a function.
return parent.getLastChild() == n
&& (parent.getBooleanProp(Node.COMPUTED_PROP_METHOD)
|| parent.getBooleanProp(Node.COMPUTED_PROP_GETTER)
|| parent.getBooleanProp(Node.COMPUTED_PROP_SETTER));
default:
return false;
}
} else {
return false;
}
}
/**
* see {@link #isClassDeclaration}
*/
public static boolean isClassDeclaration(Node n) {
return n.isClass() && isDeclarationParent(n.getParent()) && isNamedClass(n);
}
/**
* Is this node a hoisted function declaration? A function declaration in the
* scope root is hoisted to the top of the scope.
* See {@link #isFunctionDeclaration}).
*/
public static boolean isHoistedFunctionDeclaration(Node n) {
if (isFunctionDeclaration(n)) {
Node parent = n.getParent();
return parent.isScript()
|| parent.isModuleBody()
|| parent.getParent().isFunction()
|| parent.isExport();
}
return false;
}
static boolean isBlockScopedFunctionDeclaration(Node n) {
if (!isFunctionDeclaration(n)) {
return false;
}
Node current = n.getParent();
while (current != null) {
switch (current.getToken()) {
case BLOCK:
return !current.getParent().isFunction();
case FUNCTION:
case SCRIPT:
case DECLARE:
case EXPORT:
case MODULE_BODY:
return false;
default:
checkState(current.isLabel(), current);
current = current.getParent();
}
}
return false;
}
static boolean isFunctionBlock(Node n) {
return n.isBlock() && n.getParent() != null && n.getParent().isFunction();
}
/**
* Is a FUNCTION node a function expression?
*
* A function expression is a function that:
*
* - has either no name or a name that is not added to the current scope
*
- AND can be manipulated as an expression
* (assigned to variables, passed to functions, etc.)
* i.e. It is not a method declaration on a class or object literal.
*
*
* Some examples of function expressions:
*
*
* (function () {})
* (function f() {})()
* [ function f() {} ]
* var f = function f() {};
* for (function f() {};;) {}
* export default function() {}
* () => 1
*
*
* Some examples of functions that are not expressions:
*
*
* function f() {}
* if (x); else function f() {}
* for (;;) { function f() {} }
* export default function f() {}
* ({
* f() {},
* set x(v) {},
* get x() {},
* [expr]() {}
* })
* class {
* f() {}
* set x(v) {}
* get x() {}
* [expr]() {}
* }
*
*
* @param n A node
* @return Whether n is a function used within an expression.
*/
static boolean isFunctionExpression(Node n) {
return n.isFunction()
&& !NodeUtil.isFunctionDeclaration(n)
&& !NodeUtil.isMethodDeclaration(n);
}
static boolean isUnannotatedCallback(Node n) {
JSDocInfo jsdoc = getBestJSDocInfo(n);
return n.isFunction() && n.getParent().isCall() && n != n.getParent().getFirstChild()
&& jsdoc == null && !functionHasInlineJsdocs(n);
}
/**
* @return Whether the node is both a function expression and the function is named.
*/
static boolean isNamedFunctionExpression(Node n) {
return NodeUtil.isFunctionExpression(n) && !n.getFirstChild().getString().isEmpty();
}
/**
* see {@link #isFunctionExpression}
*
* @param n A node
* @return Whether n is a class used within an expression.
*/
static boolean isClassExpression(Node n) {
return n.isClass() && (!isNamedClass(n) || !isDeclarationParent(n.getParent()));
}
/**
* Returns whether n is a function with a nonempty name.
* Differs from {@link #isFunctionDeclaration} because the name might in a function expression
* and not be added to the current scope.
*
* Some named functions include
*
* (function f() {})();
* export default function f() {};
* function f() {};
* var f = function f() {};
*
*/
static boolean isNamedFunction(Node n) {
return n.isFunction() && isReferenceName(n.getFirstChild());
}
/**
* see {@link #isNamedFunction}
*
* @param n A node
* @return Whether n is a named class
*/
static boolean isNamedClass(Node n) {
return n.isClass() && isReferenceName(n.getFirstChild());
}
/**
* Returns whether this is a bleeding function (an anonymous named function
* that bleeds into the inner scope).
*/
static boolean isBleedingFunctionName(Node n) {
if (!n.isName() || n.getString().isEmpty()) {
return false;
}
Node parent = n.getParent();
return isFunctionExpression(parent) && n == parent.getFirstChild();
}
/**
* Determines if a node is a function expression that has an empty body.
*
* @param node a node
* @return whether the given node is a function expression that is empty
*/
static boolean isEmptyFunctionExpression(Node node) {
return isFunctionExpression(node) && isEmptyBlock(node.getLastChild());
}
/**
* @return Whether a function has a reference to its own "arguments" object.
*/
static boolean doesFunctionReferenceOwnArgumentsObject(Node fn) {
checkArgument(fn.isFunction());
if (fn.isArrowFunction()) {
return false;
}
return referencesArgumentsHelper(fn.getLastChild());
}
/** @return Whether any child is a reference to the "arguments" object of the root. Effectively,
* this includes arrow method bodies (which don't have their own) and excludes other functions
* which shadow the "arguments" value with their own.
*/
private static boolean referencesArgumentsHelper(Node node) {
if (node.isName() && node.getString().equals("arguments")) {
return true;
}
if (NodeUtil.isNonArrowFunction(node)) {
return false;
}
for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
if (referencesArgumentsHelper(c)) {
return true;
}
}
return false;
}
/**
* @return Whether node is a call to methodName.
* a.f(...)
* a['f'](...)
*/
static boolean isObjectCallMethod(Node callNode, String methodName) {
if (callNode.isCall()) {
Node functionIndentifyingExpression = callNode.getFirstChild();
if (isGet(functionIndentifyingExpression)) {
Node last = functionIndentifyingExpression.getLastChild();
if (last != null && last.isString()) {
String propName = last.getString();
return (propName.equals(methodName));
}
}
}
return false;
}
/**
* @return Whether the callNode represents an expression in the form of:
* x.call(...)
* x['call'](...)
*/
static boolean isFunctionObjectCall(Node callNode) {
return isObjectCallMethod(callNode, "call");
}
/**
* @return Whether the callNode represents an expression in the form of:
* x.apply(...)
* x['apply'](...)
*/
static boolean isFunctionObjectApply(Node callNode) {
return isObjectCallMethod(callNode, "apply");
}
/**
* Determines whether this node is strictly on the left hand side of an assign or var
* initialization. Notably, this does not include all L-values, only statements where the node is
* used only as an L-value.
*
* @param n The node
* @param parent Parent of the node
* @return True if n is the left hand of an assign
*/
public static boolean isNameDeclOrSimpleAssignLhs(Node n, Node parent) {
return
(parent.isAssign() && parent.getFirstChild() == n) || NodeUtil.isNameDeclaration(parent);
}
/**
* Determines whether this node is used as an L-value. Notice that sometimes
* names are used as both L-values and R-values.
*
* We treat "var x;" and "let x;" as an L-value because it's syntactically similar to
* "var x = undefined", even though it's technically not an L-value. But it kind of makes
* sense if you treat it as "assignment to 'undefined' at the top of the scope".
*
* @param n The node
* @return True if n is an L-value.
*/
public static boolean isLValue(Node n) {
switch (n.getToken()) {
case NAME:
case GETPROP:
case GETELEM:
break;
default:
return false;
}
Node parent = n.getParent();
if (parent == null) {
return false;
}
switch (parent.getToken()) {
case IMPORT_SPEC:
return parent.getLastChild() == n;
case VAR:
case LET:
case CONST:
case REST:
case PARAM_LIST:
case IMPORT:
case INC:
case DEC:
case CATCH:
return true;
case CLASS:
case FUNCTION:
case DEFAULT_VALUE:
case FOR:
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
return parent.getFirstChild() == n;
case ARRAY_PATTERN:
case STRING_KEY:
case COMPUTED_PROP:
return isLhsByDestructuring(n);
default:
return NodeUtil.isAssignmentOp(parent) && parent.getFirstChild() == n;
}
}
/**
* Determines whether this node is used as an L-value that is a declaration.
*
*
x = 5; is an L-value but does not declare a variable.
*/
public static boolean isDeclarationLValue(Node n) {
boolean isLValue = isLValue(n);
if (!isLValue) {
return false;
}
Node parent = n.getParent();
switch (parent.getToken()) {
case IMPORT_SPEC:
case VAR:
case LET:
case CONST:
case PARAM_LIST:
case IMPORT:
case CATCH:
case CLASS:
case FUNCTION:
return true;
case STRING_KEY:
return isNameDeclaration(parent.getParent().getGrandparent());
case OBJECT_PATTERN:
case ARRAY_PATTERN:
return isNameDeclaration(parent.getGrandparent());
default:
return false;
}
}
static boolean isLhsOfAssign(Node n) {
Node parent = n.getParent();
return parent != null && parent.isAssign() && parent.getFirstChild() == n;
}
public static boolean isImportedName(Node n) {
Node parent = n.getParent();
return parent.isImport() || (parent.isImportSpec() && parent.getLastChild() == n);
}
/**
* Returns the node that is effectively declaring the given target.
*
*
Examples:
*
*
* const a = 1; // getDeclaringParent(a) returns CONST
* let {[expression]: [x = 3]} = obj; // getDeclaringParent(x) returns LET
* function foo({a, b}) {}; // getDeclaringParent(a) returns PARAM_LIST
* function foo(a = 1) {}; // getDeclaringParent(a) returns PARAM_LIST
* function foo({a, b} = obj) {}; // getDeclaringParent(a) returns PARAM_LIST
* function foo(...a) {}; // getDeclaringParent(a) returns PARAM_LIST
* function foo() {}; // gotRootTarget(foo) returns FUNCTION
* class foo {}; // gotRootTarget(foo) returns CLASS
* import foo from './foo'; // getDeclaringParent(foo) returns IMPORT
* import {foo} from './foo'; // getDeclaringParent(foo) returns IMPORT
* import {foo as bar} from './foo'; // getDeclaringParent(bar) returns IMPORT
* } catch (err) { // getDeclaringParent(err) returns CATCH
*
*
* @param targetNode a NAME, OBJECT_PATTERN, or ARRAY_PATTERN
* @return node of type LET, CONST, VAR, FUNCTION, CLASS, PARAM_LIST, CATCH, or IMPORT
* @throws IllegalStateException if targetNode is not actually used as a declaration target
*/
public static Node getDeclaringParent(Node targetNode) {
Node rootTarget = getRootTarget(targetNode);
Node parent = rootTarget.getParent();
if (parent.isRest() || parent.isDefaultValue()) {
// e.g. `function foo(targetNode1 = default, ...targetNode2) {}`
parent = parent.getParent();
checkState(parent.isParamList(), parent);
} else if (parent.isDestructuringLhs()) {
// e.g. `let [a, b] = something;` targetNode is `[a, b]`
parent = parent.getParent();
checkState(isNameDeclaration(parent), parent);
} else if (parent.isClass() || parent.isFunction()) {
// e.g. `function targetNode() {}`
// e.g. `class targetNode {}`
checkState(targetNode == parent.getFirstChild(), targetNode);
} else if (parent.isImportSpec()) {
// e.g. `import {foo as targetNode} from './foo';
checkState(targetNode == parent.getSecondChild(), targetNode);
// import -> import_specs -> import_spec
// we want import
parent = parent.getGrandparent();
checkState(parent.isImport(), parent);
} else {
// e.g. `function foo(targetNode) {};`
// e.g. `let targetNode = something;`
// e.g. `import targetNode from './foo';
// e.g. `} catch (foo) {`
checkState(
parent.isParamList()
|| isNameDeclaration(parent)
|| parent.isImport()
|| parent.isCatch(),
parent);
}
return parent;
}
/**
* Returns the outermost target enclosing the given assignment target.
*
* Returns targetNode itself if there is no enclosing target.
*
*
Examples:
*
* const a = 1; // getRootTarget(a) returns a
* let {[expression]: [x = 3]} = obj; // getRootTarget(x) returns {[expression]: [x = 3]}
* {a = 1} = obj; // getRootTarget(a) returns {a = 1}
* {[expression]: [x = 3]} = obj; // getRootTarget(x) returns {[expression]: [x = 3]}
* function foo({a, b}) {}; // getRootTarget(a) returns {a, b}
* function foo(a = 1) {}; // getRootTarget(a) returns a
* function foo({a, b} = obj) {}; // getRootTarget(a) returns a
* function foo(...a) {}; // getRootTarget(a) returns a
* function foo() {}; // gotRootTarget(foo) returns foo
* class foo {}; // gotRootTarget(foo) returns foo
* import foo from './foo'; // getRootTarget(foo) returns foo
* import {foo} from './foo'; // getRootTarget(foo) returns foo
* import {foo as bar} from './foo'; // getRootTarget(bar) returns bar
*
*
* @param targetNode
* @throws IllegalStateException if targetNode is not actually used as a target
*/
public static Node getRootTarget(Node targetNode) {
Node enclosingTarget = targetNode;
for (Node nextTarget = getEnclosingTarget(enclosingTarget);
nextTarget != null;
nextTarget = getEnclosingTarget(enclosingTarget)) {
enclosingTarget = nextTarget;
}
return enclosingTarget;
}
/**
* Returns the immediately enclosing target node for a given target node, or null if none found.
*
* @see #getRootTarget(Node) for examples
* @param targetNode
*/
@Nullable
private static Node getEnclosingTarget(Node targetNode) {
checkState(checkNotNull(targetNode).isValidAssignmentTarget(), targetNode);
Node parent = checkNotNull(targetNode.getParent(), targetNode);
boolean targetIsFirstChild = parent.getFirstChild() == targetNode;
if (parent.isDefaultValue() || parent.isRest()) {
// in `([something = targetNode] = x)` targetNode isn't actually acting
// as a target.
checkState(targetIsFirstChild, parent);
// The DEFAULT_VALUE or REST occupies the place where the assignment target it contains would
// otherwise be in the AST, so pretend it is the target for the logic below.
targetNode = parent;
parent = checkNotNull(targetNode.getParent());
targetIsFirstChild = targetNode == parent.getFirstChild();
}
switch (parent.getToken()) {
case ARRAY_PATTERN:
// e.g. ([targetNode] = something)
return parent;
case OBJECT_PATTERN:
// e.g. ({...rest} = something);
return parent;
case COMPUTED_PROP:
// e.g. ({[expression]: targetNode} = something)
// e.g. ({[expression]: targetNode = default} = something)
// make sure the effective target (targetNode or DEFAULT_VALUE containing it)
// isn't the expression part
checkState(!targetIsFirstChild, parent);
// otherwise the same as STRING_KEY so fall through
case STRING_KEY:
// e.g. ({parent: targetNode} = something)
Node grandparent = checkNotNull(parent.getParent(), parent);
checkState(grandparent.isObjectPattern(), grandparent);
return grandparent;
case PARAM_LIST:
// e.g. `function foo(targetNode) {}`
case LET:
case CONST:
case VAR:
// non-destructured declarations
// e.g. `let targetNode = 3;`
return null;
case FUNCTION:
case CLASS:
// e.g. `function targetNode() {}`
// e.g. `class targetNode {}`
checkState(targetIsFirstChild, targetNode);
return null;
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
// e.g. `for ({length} in obj) {}` // targetNode is `{length}`
// e.g. `for ({length} of obj) {}` // targetNode is `{length}`
checkState(targetIsFirstChild, targetNode);
return null;
case DESTRUCTURING_LHS:
// destructured declarations
// e.g. `let [a] = 3`; // targetNode is `[a]`
checkState(targetIsFirstChild, targetNode);
return null;
case IMPORT:
// e.g. `import targetNode from './foo/bar';`
return null;
case IMPORT_SPEC:
// e.g. `import {bar as targetNode} from './foo/bar';`
// e.g. `import {targetNode} from './foo/bar';` // AST will have {targetNode as targetNode}
checkState(!targetIsFirstChild, parent);
return null;
case CATCH:
// e.g. `try {} catch (foo) {}`
return null;
default:
// e.g. targetNode = something
checkState(isAssignmentOp(parent) && targetIsFirstChild, parent);
return null;
}
}
/**
* Returns true if the node is a lhs value of a destructuring assignment.
*
* For example, x in {@code var [x] = [1];}, {@code var [...x] = [1];}, and {@code var {a: x} =
* {a: 1}} or a.b in {@code ([a.b] = [1]);} or {@code ({key: a.b} = {key: 1});}
*/
public static boolean isLhsByDestructuring(Node n) {
switch (n.getToken()) {
case NAME:
case GETPROP:
case GETELEM:
return isLhsByDestructuringHelper(n);
default:
return false;
}
}
/**
* Returns true if the given node is either an LHS node in a destructuring pattern or if one of
* its descendants contains an LHS node in a destructuring pattern. For example, in {@code var {a:
* b = 3}}}, this returns true given the NAME b or the DEFAULT_VALUE node containing b.
*/
private static boolean isLhsByDestructuringHelper(Node n) {
Node parent = n.getParent();
Node grandparent = n.getGrandparent();
switch (parent.getToken()) {
case ARRAY_PATTERN: // `b` in `var [b] = ...`
case REST: // `b` in `var [...b] = ...`
return true;
case COMPUTED_PROP:
if (n.isFirstChildOf(parent)) {
return false;
}
// Fall through.
case STRING_KEY:
return grandparent.isObjectPattern(); // the "b" in "var {a: b} = ..."
case DEFAULT_VALUE:
if (n.isFirstChildOf(parent)) {
// The first child of a DEFAULT_VALUE is a NAME node and a potential LHS.
// The second child is the value, so never a LHS node.
return isLhsByDestructuringHelper(parent);
}
return false;
default:
return false;
}
}
/**
* Determines whether a node represents a possible object literal key (e.g. key1 in {key1: value1,
* key2: value2}). Computed properties are excluded here (see b/111621528). This method does not
* check whether the node is actually in an object literal! it also returns true for object
* pattern keys, and member functions/getters in ES6 classes.
*
* @param node A node
*/
static boolean mayBeObjectLitKey(Node node) {
switch (node.getToken()) {
case STRING_KEY:
case GETTER_DEF:
case SETTER_DEF:
case MEMBER_FUNCTION_DEF:
return true;
default:
return false;
}
}
/**
* Determines whether a node represents an object literal key (e.g. key1 in {key1: value1, key2:
* value2}) and is in an object literal. Computed properties are excluded here (see b/111621528).
*
* @param node A node
*/
static boolean isObjectLitKey(Node node) {
return node.getParent().isObjectLit() && mayBeObjectLitKey(node);
}
/**
* Get the name of an object literal key.
*
* @param key A node
*/
static String getObjectLitKeyName(Node key) {
Node keyNode = getObjectLitKeyNode(key);
if (keyNode != null) {
return keyNode.getString();
}
throw new IllegalStateException("Unexpected node type: " + key);
}
/**
* Get the Node that defines the name of an object literal key.
*
* @param key A node
*/
static Node getObjectLitKeyNode(Node key) {
switch (key.getToken()) {
case STRING_KEY:
case GETTER_DEF:
case SETTER_DEF:
case MEMBER_FUNCTION_DEF:
return key;
case COMPUTED_PROP:
return key.getFirstChild().isString() ? key.getFirstChild() : null;
default:
break;
}
throw new IllegalStateException("Unexpected node type: " + key);
}
/**
* Determine whether the destructuring object pattern is nested
*
* @param n object pattern node
*/
static boolean isNestedObjectPattern(Node n) {
checkState(n.isObjectPattern());
for (Node key = n.getFirstChild(); key != null; key = key.getNext()) {
Node value = key.getFirstChild();
if (value != null
&& (value.isObjectLit() || value.isArrayLit() || value.isDestructuringPattern())) {
return true;
}
}
return false;
}
/**
* Determine whether the destructuring array pattern is nested
*
* @param n array pattern node
*/
static boolean isNestedArrayPattern(Node n) {
checkState(n.isArrayPattern());
for (Node key = n.getFirstChild(); key != null; key = key.getNext()) {
if (key.hasChildren()) {
return true;
}
}
return false;
}
/**
* Determines whether a node represents an object literal get or set key
* (e.g. key1 in {get key1() {}, set key2(a){}).
*
* @param node A node
*/
static boolean isGetOrSetKey(Node node) {
switch (node.getToken()) {
case GETTER_DEF:
case SETTER_DEF:
return true;
case COMPUTED_PROP:
return node.getBooleanProp(Node.COMPUTED_PROP_GETTER)
|| node.getBooleanProp(Node.COMPUTED_PROP_SETTER);
default:
break;
}
return false;
}
/**
* Converts an operator's token value (see {@link Token}) to a string
* representation.
*
* @param operator the operator's token value to convert
* @return the string representation or {@code null} if the token value is
* not an operator
*/
public static String opToStr(Token operator) {
switch (operator) {
case BITOR:
return "|";
case OR:
return "||";
case BITXOR:
return "^";
case AND:
return "&&";
case BITAND:
return "&";
case SHEQ:
return "===";
case EQ:
return "==";
case NOT:
return "!";
case NE:
return "!=";
case SHNE:
return "!==";
case LSH:
return "<<";
case IN:
return "in";
case LE:
return "<=";
case LT:
return "<";
case URSH:
return ">>>";
case RSH:
return ">>";
case GE:
return ">=";
case GT:
return ">";
case MUL:
return "*";
case DIV:
return "/";
case MOD:
return "%";
case EXPONENT:
return "**";
case BITNOT:
return "~";
case ADD:
case POS:
return "+";
case SUB:
case NEG:
return "-";
case ASSIGN:
return "=";
case ASSIGN_BITOR:
return "|=";
case ASSIGN_BITXOR:
return "^=";
case ASSIGN_BITAND:
return "&=";
case ASSIGN_LSH:
return "<<=";
case ASSIGN_RSH:
return ">>=";
case ASSIGN_URSH:
return ">>>=";
case ASSIGN_ADD:
return "+=";
case ASSIGN_SUB:
return "-=";
case ASSIGN_MUL:
return "*=";
case ASSIGN_EXPONENT:
return "**=";
case ASSIGN_DIV:
return "/=";
case ASSIGN_MOD:
return "%=";
case VOID:
return "void";
case TYPEOF:
return "typeof";
case INSTANCEOF:
return "instanceof";
default:
return null;
}
}
/**
* Converts an operator's token value (see {@link Token}) to a string
* representation or fails.
*
* @param operator the operator's token value to convert
* @return the string representation
* @throws Error if the token value is not an operator
*/
static String opToStrNoFail(Token operator) {
String res = opToStr(operator);
if (res == null) {
throw new Error("Unknown op " + operator);
}
return res;
}
/** @return true if n or any of its descendants are of the specified type. */
static boolean containsType(Node node, Token type, Predicate traverseChildrenPred) {
return has(node, new MatchNodeType(type), traverseChildrenPred);
}
/**
* @return true if n or any of its descendants are of the specified type.
*/
public static boolean containsType(Node node, Token type) {
return containsType(node, type, Predicates.alwaysTrue());
}
/**
* Given a node tree, finds all the VAR declarations in that tree that are
* not in an inner scope. Then adds a new VAR node at the top of the current
* scope that redeclares them, if necessary.
*/
static void redeclareVarsInsideBranch(Node branch) {
Collection vars = getVarsDeclaredInBranch(branch);
if (vars.isEmpty()) {
return;
}
Node parent = getAddingRoot(branch);
for (Node nameNode : vars) {
Node var = IR.var(
IR.name(nameNode.getString())
.srcref(nameNode))
.srcref(nameNode);
copyNameAnnotations(nameNode, var.getFirstChild());
parent.addChildToFront(var);
}
}
/**
* Copy any annotations that follow a named value.
* @param source
* @param destination
*/
static void copyNameAnnotations(Node source, Node destination) {
if (source.getBooleanProp(Node.IS_CONSTANT_NAME)) {
destination.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
}
/**
* Gets a Node at the top of the current scope where we can add new var
* declarations as children.
*/
private static Node getAddingRoot(Node n) {
Node addingRoot = null;
Node ancestor = n;
crawl_ancestors: while (null != (ancestor = ancestor.getParent())) {
switch (ancestor.getToken()) {
case SCRIPT:
case MODULE_BODY:
addingRoot = ancestor;
break crawl_ancestors;
case FUNCTION:
addingRoot = ancestor.getLastChild();
break crawl_ancestors;
default:
continue crawl_ancestors;
}
}
// make sure that the adding root looks ok
checkState(addingRoot.isBlock() || addingRoot.isModuleBody() || addingRoot.isScript());
checkState(!addingRoot.hasChildren() || !addingRoot.getFirstChild().isScript());
return addingRoot;
}
public static Node newDeclaration(Node lhs, @Nullable Node rhs, Token declarationType) {
if (rhs == null) {
return IR.declaration(lhs, declarationType);
}
return IR.declaration(lhs, rhs, declarationType);
}
/**
* Creates a node representing a qualified name.
*
* @param name A qualified name (e.g. "foo" or "foo.bar.baz")
* @return A NAME or GETPROP node
*/
public static Node newQName(
AbstractCompiler compiler, String name) {
int endPos = name.indexOf('.');
if (endPos == -1) {
return newName(compiler, name);
}
Node node;
String nodeName = name.substring(0, endPos);
if ("this".equals(nodeName)) {
node = IR.thisNode();
} else if ("super".equals(nodeName)) {
node = IR.superNode();
} else {
node = newName(compiler, nodeName);
}
int startPos;
do {
startPos = endPos + 1;
endPos = name.indexOf('.', startPos);
String part = (endPos == -1 ? name.substring(startPos) : name.substring(startPos, endPos));
Node propNode = IR.string(part);
propNode.setLength(part.length());
if (compiler.getCodingConvention().isConstantKey(part)) {
propNode.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
int length = node.getLength() + ".".length() + part.length();
node = IR.getprop(node, propNode);
node.setLength(length);
} while (endPos != -1);
return node;
}
/**
* Creates a node representing a qualified name, copying over the source
* location information from the basis node and assigning the given original
* name to the node.
*
* @param name A qualified name (e.g. "foo" or "foo.bar.baz")
* @param basisNode The node that represents the name as currently found in
* the AST.
* @param originalName The original name of the item being represented by the
* NAME node. Used for debugging information.
*
* @return A NAME or GETPROP node
*/
static Node newQName(
AbstractCompiler compiler, String name, Node basisNode,
String originalName) {
Node node = newQName(compiler, name);
useSourceInfoForNewQName(node, basisNode);
if (!originalName.equals(node.getOriginalName())) {
// If basisNode already had the correct original name, then it will already be set correctly.
// Setting it again will force the QName node to have a different property list from all of
// its children, causing greater memory consumption.
node.setOriginalName(originalName);
}
return node;
}
/**
* Creates a property access on the {@code context} tree.
*/
public static Node newPropertyAccess(AbstractCompiler compiler, Node context, String name) {
Node propNode = IR.getprop(context, IR.string(name));
if (compiler.getCodingConvention().isConstantKey(name)) {
propNode.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
return propNode;
}
/**
* Creates a node representing a qualified name.
*
* @param name A qualified name (e.g. "foo" or "foo.bar.baz")
* @return A VAR node, or an EXPR_RESULT node containing an ASSIGN or NAME node.
*/
public static Node newQNameDeclaration(
AbstractCompiler compiler, String name, Node value, JSDocInfo info) {
return newQNameDeclaration(compiler, name, value, info, Token.VAR);
}
/**
* Creates a node representing a qualified name.
*
* @param name A qualified name (e.g. "foo" or "foo.bar.baz")
* @param type Must be VAR, CONST, or LET. Ignored if {@code name} is dotted.
* @return A VAR/CONST/LET node, or an EXPR_RESULT node containing an ASSIGN or NAME node.
*/
public static Node newQNameDeclaration(
AbstractCompiler compiler, String name, Node value, JSDocInfo info, Token type) {
checkState(type == Token.VAR || type == Token.LET || type == Token.CONST, type);
Node result;
Node nameNode = newQName(compiler, name);
if (nameNode.isName()) {
result =
value == null ? IR.declaration(nameNode, type) : IR.declaration(nameNode, value, type);
result.setJSDocInfo(info);
} else if (value != null) {
result = IR.exprResult(IR.assign(nameNode, value));
result.getFirstChild().setJSDocInfo(info);
} else {
result = IR.exprResult(nameNode);
result.getFirstChild().setJSDocInfo(info);
}
return result;
}
/**
* Custom update new QName node with source info from another node.
*
* This is very similar to {@link Node#useSourceInfoIfMissingFromForTree(Node)}, but it avoids
* overwriting the length field of the nodes.
* TODO(bradfordcsmith): Eliminate the need for this custom method.
*/
private static void useSourceInfoForNewQName(Node newQName, Node basisNode) {
if (newQName.getStaticSourceFile() == null) {
newQName.setStaticSourceFileFrom(basisNode);
newQName.setSourceEncodedPosition(basisNode.getSourcePosition());
}
if (newQName.getOriginalName() == null) {
newQName.putProp(Node.ORIGINALNAME_PROP, basisNode.getOriginalName());
}
for (Node child = newQName.getFirstChild(); child != null; child = child.getNext()) {
useSourceInfoForNewQName(child, basisNode);
}
}
/**
* Gets the root node of a qualified name. Must be either NAME, THIS or SUPER.
*/
static Node getRootOfQualifiedName(Node qName) {
for (Node current = qName; true; current = current.getFirstChild()) {
if (current.isName() || current.isThis() || current.isSuper()) {
return current;
}
checkState(current.isGetProp(), "Not a getprop node: ", current);
}
}
static int getLengthOfQname(Node qname) {
int result = 1;
while (qname.isGetProp() || qname.isGetElem()) {
result++;
qname = qname.getFirstChild();
}
checkState(qname.isName());
return result;
}
private static Node newName(AbstractCompiler compiler, String name) {
Node nameNode = IR.name(name);
nameNode.setLength(name.length());
if (compiler.getCodingConvention().isConstant(name)) {
nameNode.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
return nameNode;
}
/**
* Creates a new node representing an *existing* name, copying over the source
* location information from the basis node.
*
* @param name The name for the new NAME node.
* @param srcref The node that represents the name as currently found in
* the AST.
*
* @return The node created.
*/
static Node newName(AbstractCompiler compiler, String name, Node srcref) {
return newName(compiler, name).srcref(srcref);
}
/**
* Creates a new node representing an *existing* name, copying over the source
* location information from the basis node and assigning the given original
* name to the node.
*
* @param name The name for the new NAME node.
* @param basisNode The node that represents the name as currently found in
* the AST.
* @param originalName The original name of the item being represented by the
* NAME node. Used for debugging information.
*
* @return The node created.
*/
static Node newName(
AbstractCompiler compiler, String name,
Node basisNode, String originalName) {
Node nameNode = newName(compiler, name, basisNode);
nameNode.setOriginalName(originalName);
return nameNode;
}
/**
* Test if all characters in the string are in the Basic Latin (aka ASCII) character set - that
* they have UTF-16 values equal to or below 0x7f. This check can find which identifiers with
* Unicode characters need to be escaped in order to allow resulting files to be processed by
* non-Unicode aware UNIX tools and editors. * See
* http://en.wikipedia.org/wiki/Latin_characters_in_Unicode for more on Basic Latin.
*
* @param s The string to be checked for ASCII-goodness.
* @return True if all characters in the string are in Basic Latin set.
*/
static boolean isLatin(String s) {
int len = s.length();
for (int index = 0; index < len; index++) {
char c = s.charAt(index);
if (c > LARGEST_BASIC_LATIN) {
return false;
}
}
return true;
}
/**
* Determines whether the given name is a valid variable name.
*/
static boolean isValidSimpleName(String name) {
return TokenStream.isJSIdentifier(name)
&& !TokenStream.isKeyword(name)
// no Unicode escaped characters - some browsers are less tolerant
// of Unicode characters that might be valid according to the
// language spec.
// Note that by this point, Unicode escapes have been converted
// to UTF-16 characters, so we're only searching for character
// values, not escapes.
&& isLatin(name);
}
@Deprecated
public static boolean isValidQualifiedName(LanguageMode mode, String name) {
return isValidQualifiedName(mode.toFeatureSet(), name);
}
/** Determines whether the given name is a valid qualified name. */
public static boolean isValidQualifiedName(FeatureSet mode, String name) {
if (name.endsWith(".") || name.startsWith(".")) {
return false;
}
List parts = Splitter.on('.').splitToList(name);
for (String part : parts) {
if (!isValidPropertyName(mode, part)) {
return false;
}
}
return isValidSimpleName(parts.get(0));
}
/**
* Determines whether the given name can appear on the right side of the dot operator. Many
* properties (like reserved words) cannot, in ES3.
*/
static boolean isValidPropertyName(FeatureSet mode, String name) {
if (isValidSimpleName(name)) {
return true;
} else {
return mode.has(Feature.KEYWORDS_AS_PROPERTIES) && TokenStream.isKeyword(name);
}
}
private static class VarCollector implements Visitor {
final Map vars = new LinkedHashMap<>();
@Override
public void visit(Node n) {
if (n.isName()) {
Node parent = n.getParent();
if (parent != null && parent.isVar()) {
String name = n.getString();
vars.putIfAbsent(name, n);
}
}
}
}
/**
* Retrieves vars declared in the current node tree, excluding descent scopes.
*/
static Collection getVarsDeclaredInBranch(Node root) {
VarCollector collector = new VarCollector();
visitPreOrder(
root,
collector,
MATCH_NOT_FUNCTION);
return collector.vars.values();
}
private static void getLhsNodesHelper(Node n, List lhsNodes) {
switch (n.getToken()) {
case IMPORT:
getLhsNodesHelper(n.getFirstChild(), lhsNodes);
getLhsNodesHelper(n.getSecondChild(), lhsNodes);
return;
case VAR:
case CONST:
case LET:
case OBJECT_PATTERN:
case ARRAY_PATTERN:
case PARAM_LIST:
case IMPORT_SPECS:
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
getLhsNodesHelper(child, lhsNodes);
}
return;
case DESTRUCTURING_LHS:
case DEFAULT_VALUE:
case CATCH:
case REST:
case CAST:
getLhsNodesHelper(n.getFirstChild(), lhsNodes);
return;
case IMPORT_SPEC:
case COMPUTED_PROP:
case STRING_KEY:
getLhsNodesHelper(n.getLastChild(), lhsNodes);
return;
case NAME:
case IMPORT_STAR:
lhsNodes.add(n);
return;
case GETPROP:
case GETELEM:
// Not valid in declarations but may appear in assignments.
lhsNodes.add(n);
return;
case EMPTY:
return;
case FOR_IN:
case FOR_OF:
case FOR_AWAIT_OF:
// Enhanced for loops assign to variables in their first child
// e.g.
// for (some.prop in someObj) {...
// for ({a, b} of someIterable) {...
getLhsNodesHelper(n.getFirstChild(), lhsNodes);
return;
default:
if (isAssignmentOp(n)) {
getLhsNodesHelper(n.getFirstChild(), lhsNodes);
} else {
throw new IllegalStateException("Invalid node in lhs: " + n);
}
}
}
/**
* Retrieves lhs nodes declared or assigned in a given assigning parent node.
*
* An assigning parent node is one that assigns a value to one or more LHS nodes.
*/
public static List findLhsNodesInNode(Node assigningParent) {
checkArgument(
isNameDeclaration(assigningParent)
|| assigningParent.isParamList()
|| isAssignmentOp(assigningParent)
|| assigningParent.isCatch()
|| assigningParent.isDestructuringLhs()
|| assigningParent.isDefaultValue()
|| assigningParent.isImport()
// enhanced for loops assign to loop variables
|| isEnhancedFor(assigningParent),
assigningParent);
ArrayList lhsNodes = new ArrayList<>();
getLhsNodesHelper(assigningParent, lhsNodes);
return lhsNodes;
}
/**
* @return {@code true} if the node is a definition with Object.defineProperties
*/
static boolean isObjectDefinePropertiesDefinition(Node n) {
if (!n.isCall() || !n.hasXChildren(3)) {
return false;
}
Node first = n.getFirstChild();
if (!first.isGetProp()) {
return false;
}
Node prop = first.getLastChild();
return prop.getString().equals("defineProperties")
&& isKnownGlobalObjectReference(first.getFirstChild());
}
private static boolean isKnownGlobalObjectReference(Node n) {
switch (n.getToken()) {
case NAME:
return n.getString().equals("Object");
case GETPROP:
return n.matchesQualifiedName("$jscomp.global.Object")
|| n.matchesQualifiedName("$jscomp$global.Object");
default:
return false;
}
}
/** Returns {@code true} if the node is a definition with Object.defineProperty. */
static boolean isObjectDefinePropertyDefinition(Node n) {
if (!n.isCall() || !n.hasXChildren(4)) {
return false;
}
Node first = n.getFirstChild();
if (!first.isGetProp()) {
return false;
}
Node prop = first.getLastChild();
return prop.getString().equals("defineProperty")
&& isKnownGlobalObjectReference(first.getFirstChild());
}
/**
* @return A list of STRING_KEY properties defined by a Object.defineProperties(o, {...}) call
*/
static Iterable getObjectDefinedPropertiesKeys(Node definePropertiesCall) {
checkArgument(NodeUtil.isObjectDefinePropertiesDefinition(definePropertiesCall));
List properties = new ArrayList<>();
Node objectLiteral = definePropertiesCall.getLastChild();
for (Node key : objectLiteral.children()) {
if (!key.isStringKey()) {
continue;
}
properties.add(key);
}
return properties;
}
/**
* @return {@code true} if the node an assignment to a prototype property of
* some constructor.
*/
public static boolean isPrototypePropertyDeclaration(Node n) {
return isExprAssign(n) && isPrototypeProperty(n.getFirstFirstChild());
}
/**
* @return Whether the node represents a qualified prototype property.
*/
static boolean isPrototypeProperty(Node n) {
if (!n.isGetProp()) {
return false;
}
Node recv = n.getFirstChild();
return recv.isGetProp() && recv.getLastChild().getString().equals("prototype");
}
/**
* @return Whether the node represents a prototype method.
*/
static boolean isPrototypeMethod(Node n) {
if (!n.isFunction()) {
return false;
}
Node assignNode = n.getParent();
if (!assignNode.isAssign()) {
return false;
}
return isPrototypePropertyDeclaration(assignNode.getParent());
}
static boolean isPrototypeAssignment(Node getProp) {
if (!getProp.isGetProp()) {
return false;
}
Node parent = getProp.getParent();
return parent.isAssign() && parent.getFirstChild() == getProp
&& parent.getFirstChild().getLastChild().getString().equals("prototype");
}
/**
* Determines whether this node is testing for the existence of a property.
* If true, we will not emit warnings about a missing property.
*
* @param propAccess The GETPROP or GETELEM being tested.
*/
static boolean isPropertyTest(AbstractCompiler compiler, Node propAccess) {
Node parent = propAccess.getParent();
switch (parent.getToken()) {
case CALL:
return parent.getFirstChild() != propAccess
&& compiler.getCodingConvention().isPropertyTestFunction(parent);
case IF:
case WHILE:
case DO:
case FOR:
case FOR_IN:
return NodeUtil.getConditionExpression(parent) == propAccess;
case INSTANCEOF:
case TYPEOF:
case AND:
case OR:
return true;
case NE:
case SHNE: {
Node other = parent.getFirstChild() == propAccess
? parent.getSecondChild() : parent.getFirstChild();
return isUndefined(other);
}
case HOOK:
return parent.getFirstChild() == propAccess;
case NOT:
return parent.getParent().isOr()
&& parent.getParent().getFirstChild() == parent;
case CAST:
return isPropertyTest(compiler, parent);
default:
break;
}
return false;
}
static boolean isPropertyAbsenceTest(Node propAccess) {
Node parent = propAccess.getParent();
switch (parent.getToken()) {
case EQ:
case SHEQ: {
Node other = parent.getFirstChild() == propAccess
? parent.getSecondChild() : parent.getFirstChild();
return isUndefined(other);
}
default:
return false;
}
}
/**
* @param qName A qualified name node representing a class prototype, or a property on that
* prototype, e.g. foo.Bar.prototype, or foo.Bar.prototype.toString.
* @return The class name part of a qualified prototype name, e.g. foo.Bar.
*/
static Node getPrototypeClassName(Node qName) {
if (!qName.isGetProp()) {
return null;
}
if (qName.getLastChild().getString().equals("prototype")) {
return qName.getFirstChild();
}
Node recv = qName.getFirstChild();
if (recv.isGetProp() && recv.getLastChild().getString().equals("prototype")) {
return recv.getFirstChild();
}
return null;
}
/**
* @return The string property name part of a qualified prototype name.
*/
static String getPrototypePropertyName(Node qName) {
String qNameStr = qName.getQualifiedName();
int prototypeIdx = qNameStr.lastIndexOf(".prototype.");
int memberIndex = prototypeIdx + ".prototype".length() + 1;
return qNameStr.substring(memberIndex);
}
/** Create a node for an empty result expression: "void 0" */
public static Node newUndefinedNode(Node srcReferenceNode) {
Node node = IR.voidNode(IR.number(0));
if (srcReferenceNode != null) {
node.useSourceInfoFromForTree(srcReferenceNode);
}
return node;
}
/**
* Create a VAR node containing the given name and initial value expression.
*/
static Node newVarNode(String name, Node value) {
Node lhs = IR.name(name);
if (value != null) {
lhs.srcref(value);
}
return newVarNode(lhs, value);
}
/**
* Create a VAR node containing the given lhs (name or destructuring pattern) and
* initial value expression.
*/
static Node newVarNode(Node lhs, Node value) {
if (lhs.isDestructuringPattern()) {
checkNotNull(value);
return IR.var(new Node(Token.DESTRUCTURING_LHS, lhs, value).srcref(lhs)).srcref(lhs);
} else {
checkState(lhs.isName() && !lhs.hasChildren());
if (value != null) {
lhs.addChildToBack(value);
}
return IR.var(lhs).srcref(lhs);
}
}
public static Node emptyFunction() {
return IR.function(IR.name(""), IR.paramList(), IR.block());
}
/**
* A predicate for matching name nodes with the specified node.
*/
static class MatchNameNode implements Predicate{
final String name;
MatchNameNode(String name){
this.name = name;
}
@Override
public boolean apply(Node n) {
return n.isName() && n.getString().equals(name);
}
}
/**
* A predicate for matching nodes with the specified type.
*/
static class MatchNodeType implements Predicate{
final Token type;
MatchNodeType(Token type){
this.type = type;
}
@Override
public boolean apply(Node n) {
return n.getToken() == type;
}
}
/**
* A predicate for matching var, let, const, class or function declarations.
*/
static class MatchDeclaration implements Predicate {
@Override
public boolean apply(Node n) {
return isDeclaration(n);
}
}
static final Predicate MATCH_NOT_FUNCTION = n -> !n.isFunction();
/**
* A predicate for matching anything except for a non-arrow function.
*
* Useful to avoid traversing into scopes that don't share the same values for {@code this},
* {@code super}, or {@code arguments}.
*/
static final Predicate MATCH_ANYTHING_BUT_NON_ARROW_FUNCTION =
n -> !NodeUtil.isNonArrowFunction(n);
/**
* A predicate for matching statements without exiting the current scope.
*/
static class MatchShallowStatement implements Predicate{
@Override
public boolean apply(Node n) {
Node parent = n.getParent();
return n.isRoot()
|| n.isBlock()
|| (!n.isFunction()
&& (parent == null || isControlStructure(parent) || isStatementBlock(parent)));
}
}
/**
* Finds the number of times a type is referenced within the node tree.
*/
static int getNodeTypeReferenceCount(
Node node, Token type, Predicate traverseChildrenPred) {
return getCount(node, new MatchNodeType(type), traverseChildrenPred);
}
/** Whether a simple name is referenced within the node tree. */
static boolean isNameReferenced(Node node, String name, Predicate traverseChildrenPred) {
return has(node, new MatchNameNode(name), traverseChildrenPred);
}
/**
* Whether a simple name is referenced within the node tree.
*/
static boolean isNameReferenced(Node node, String name) {
return isNameReferenced(node, name, Predicates.alwaysTrue());
}
/**
* Finds the number of times a simple name is referenced within the node tree.
*/
static int getNameReferenceCount(Node node, String name) {
return getCount(node, new MatchNameNode(name), Predicates.alwaysTrue());
}
/** @return Whether the predicate is true for the node or any of its descendants. */
public static boolean has(Node node, Predicate pred, Predicate traverseChildrenPred) {
if (pred.apply(node)) {
return true;
}
if (!traverseChildrenPred.apply(node)) {
return false;
}
for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
if (has(c, pred, traverseChildrenPred)) {
return true;
}
}
return false;
}
/**
* @return The number of times the predicate is true for the node
* or any of its descendants.
*/
public static int getCount(
Node n, Predicate pred, Predicate traverseChildrenPred) {
int total = 0;
if (pred.apply(n)) {
total++;
}
if (traverseChildrenPred.apply(n)) {
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
total += getCount(c, pred, traverseChildrenPred);
}
}
return total;
}
/**
* Interface for use with the visit method.
* @see #visit
*/
public static interface Visitor {
void visit(Node node);
}
/** A pre-order traversal, calling Visitor.visit for each decendent. */
public static void visitPreOrder(Node node, Visitor visitor) {
visitPreOrder(node, visitor, Predicates.alwaysTrue());
}
/** A pre-order traversal, calling Visitor.visit for each child matching the predicate. */
public static void visitPreOrder(
Node node, Visitor visitor, Predicate traverseChildrenPred) {
visitor.visit(node);
if (traverseChildrenPred.apply(node)) {
for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
visitPreOrder(c, visitor, traverseChildrenPred);
}
}
}
/** A post-order traversal, calling Visitor.visit for each decendent. */
public static void visitPostOrder(Node node, Visitor visitor) {
visitPostOrder(node, visitor, Predicates.alwaysTrue());
}
/** A post-order traversal, calling Visitor.visit for each descendant matching the predicate. */
public static void visitPostOrder(
Node node, Visitor visitor, Predicate traverseChildrenPred) {
if (traverseChildrenPred.apply(node)) {
for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
visitPostOrder(c, visitor, traverseChildrenPred);
}
}
visitor.visit(node);
}
/**
* @return Whether an EXPORT node has a from clause.
*/
static boolean isExportFrom(Node n) {
checkArgument(n.isExport());
return n.hasTwoChildren();
}
/**
* @return Whether a TRY node has a finally block.
*/
static boolean hasFinally(Node n) {
checkArgument(n.isTry());
return n.hasXChildren(3);
}
/**
* @return The BLOCK node containing the CATCH node (if any)
* of a TRY.
*/
static Node getCatchBlock(Node n) {
checkArgument(n.isTry());
return n.getSecondChild();
}
/**
* @return Whether BLOCK (from a TRY node) contains a CATCH.
* @see NodeUtil#getCatchBlock
*/
static boolean hasCatchHandler(Node n) {
checkArgument(n.isBlock());
return n.hasChildren() && n.getFirstChild().isCatch();
}
/**
* @param fnNode The function.
* @return The Node containing the Function parameters.
*/
public static Node getFunctionParameters(Node fnNode) {
checkArgument(fnNode.isFunction());
return fnNode.getSecondChild();
}
/**
* Counts the parameters of a function that are not marked optional or varargs.
* In ES5 functions, that's all parameters, in ES6 it's a prefix of the parameters.
* The result is an overapproximation: if a parameter is not marked as optional, it may still
* be optional, but it doesn't have a default value, and wasn't marked as optional
* during transpilation.
*/
public static int getApproxRequiredArity(Node fun) {
checkArgument(fun.isFunction());
checkArgument(getBestJSDocInfo(fun) == null, "Expected unannotated function, found: %s", fun);
int result = 0;
for (Node param : fun.getSecondChild().children()) {
if (param.isOptionalArg() || param.isVarArgs()) {
break;
}
result++;
}
return result;
}
static boolean isConstantVar(Node node, @Nullable Scope scope) {
if (isConstantName(node)) {
return true;
}
if (!node.isName() || scope == null) {
return false;
}
Var var = scope.getVar(node.getString());
return var != null && (var.isInferredConst() || var.isConst());
}
/**
* Determines whether a variable is constant:
*
* - In Normalize, any name that matches the
* {@link CodingConvention#isConstant(String)} is annotated with an
* IS_CONSTANT_NAME property.
*
*
* @param node A NAME or STRING node
* @return True if a name node represents a constant variable
*
* TODO(dimvar): this method and the next two do similar but not quite identical things. Clean up
*/
static boolean isConstantName(Node node) {
return node.getBooleanProp(Node.IS_CONSTANT_NAME);
}
/** Whether the given name is constant by coding convention. */
static boolean isConstantByConvention(
CodingConvention convention, Node node) {
Node parent = node.getParent();
if (parent.isGetProp() && node == parent.getLastChild()) {
return convention.isConstantKey(node.getString());
} else if (mayBeObjectLitKey(node)) {
return convention.isConstantKey(node.getString());
} else if (node.isName()) {
return convention.isConstant(node.getString());
}
return false;
}
/**
* Temporary function to determine if a node is constant
* in the old or new world. This does not check its inputs
* carefully because it will go away once we switch to the new
* world.
*/
static boolean isConstantDeclaration(
CodingConvention convention, JSDocInfo info, Node node) {
// TODO(b/77597706): Update this method to handle destructured declarations.
if (node.isName() && node.getParent().isConst()) {
return true;
} else if (node.isName()
&& isLhsByDestructuring(node)
&& getRootTarget(node).getGrandparent().isConst()) {
return true;
}
if (info != null && info.isConstant()) {
return true;
}
if (node.getBooleanProp(Node.IS_CONSTANT_VAR)) {
return true;
}
switch (node.getToken()) {
case NAME:
return NodeUtil.isConstantByConvention(convention, node);
case GETPROP:
return node.isQualifiedName()
&& NodeUtil.isConstantByConvention(convention, node.getLastChild());
default:
break;
}
return false;
}
static boolean functionHasInlineJsdocs(Node fn) {
if (!fn.isFunction()) {
return false;
}
// Check inline return annotation
if (fn.getFirstChild().getJSDocInfo() != null) {
return true;
}
// Check inline parameter annotations
Node param = fn.getSecondChild().getFirstChild();
while (param != null) {
if (param.getJSDocInfo() != null) {
return true;
}
param = param.getNext();
}
return false;
}
/**
* @param n The node.
* @return The source name property on the node or its ancestors.
*/
public static String getSourceName(Node n) {
String sourceName = null;
while (sourceName == null && n != null) {
sourceName = n.getSourceFileName();
n = n.getParent();
}
return sourceName;
}
/**
* @param n The node.
* @return The source name property on the node or its ancestors.
*/
public static StaticSourceFile getSourceFile(Node n) {
StaticSourceFile sourceName = null;
while (sourceName == null && n != null) {
sourceName = n.getStaticSourceFile();
n = n.getParent();
}
return sourceName;
}
/**
* @param n The node.
* @return The InputId property on the node or its ancestors.
*/
public static InputId getInputId(Node n) {
while (n != null && !n.isScript()) {
n = n.getParent();
}
return (n != null && n.isScript()) ? n.getInputId() : null;
}
// NOTE(dimvar): This method is to support IDEs using the compiler. If we end up
// needing many more methods, put them all in a separate file.
// lineNo and columNo are 1-based.
// Column number 1 represents a cursor at the start of the line.
public static Node getNodeByLineCol(Node ancestor, int lineNo, int columNo) {
checkArgument(ancestor.isScript());
Node current = ancestor;
Node result = null;
while (current != null) {
int currLineNo = current.getLineno();
checkState(current.getLineno() <= lineNo);
Node nextSibling = current.getNext();
if (nextSibling != null) {
int nextSiblingLineNo = nextSibling.getLineno();
int nextSiblingColumNo = getColumnNoBase1(nextSibling);
if (result != null
&& lineNo == nextSiblingLineNo && columNo == nextSiblingColumNo) {
// The cursor is in-between two nodes.
// If just one of them is a variable, a property, or a literal, return that one.
// Otherwise, return the node to the left of the cursor.
if (result.hasChildren() && !nextSibling.hasChildren()) {
return nextSibling;
}
return result;
}
// Check if the desired location is past the end of the current node,
// and if so, continue to the siblings.
if (lineNo > nextSiblingLineNo
|| (lineNo > currLineNo && lineNo == nextSiblingLineNo)
|| (lineNo == nextSiblingLineNo && columNo > nextSiblingColumNo)) {
current = nextSibling;
continue;
}
}
// The desired node is either current or one of its children.
int currColumNo = getColumnNoBase1(current);
if (currLineNo == lineNo) {
if (currColumNo > columNo) {
// current starts past the desired node, return.
return result;
}
if (currColumNo + current.getLength() >= columNo) {
result = current;
}
}
current = current.getFirstChild();
}
return result;
}
// This is here instead of in Node, because it's error-prone to have two methods
// in Node for getting the column. So, we implement the method only for the specific
// use case of getNodeByLineCol.
private static int getColumnNoBase1(Node n) {
return n.getCharno() + 1;
}
/**
* A new CALL node with the "FREE_CALL" set based on call target.
*/
static Node newCallNode(Node callTarget, Node... parameters) {
boolean isFreeCall = !isGet(callTarget);
Node call = IR.call(callTarget);
call.putBooleanProp(Node.FREE_CALL, isFreeCall);
for (Node parameter : parameters) {
call.addChildToBack(parameter);
}
return call;
}
/**
* Whether the result of the expression node is known to be a primitive value or an object that
* has not yet escaped.
*
* This guarantee is different than that provided by isLiteralValue (where literal values are
* immune to side-effects if unescaped) or isImmutableValue (which can be safely aliased).
*
*
The concept of "local values" allow for the containment of side-effect operations. For
* example, setting a property on a local value does not produce a global side-effect.
*
*
Note that the concept of "local value" is not deep, it does not say anything about the
* properties of the "local value" (all class instances have "constructor" properties that are not
* local values for instance).
*
*
Note that this method only provides the starting state of the expression result, it does not
* guarantee that the value is forever a local value. If the containing method has any non-local
* side-effect, "local values" may escape.
*/
static boolean evaluatesToLocalValue(Node value) {
switch (value.getToken()) {
case ASSIGN:
// A result that is aliased by a non-local name, is the effectively the
// same as returning a non-local name, but this doesn't matter if the
// value is immutable.
return NodeUtil.isImmutableValue(value.getLastChild());
case COMMA:
return evaluatesToLocalValue(value.getLastChild());
case AND:
case OR:
return evaluatesToLocalValue(value.getFirstChild())
&& evaluatesToLocalValue(value.getLastChild());
case HOOK:
return evaluatesToLocalValue(value.getSecondChild())
&& evaluatesToLocalValue(value.getLastChild());
case THIS:
case SUPER:
return false;
case NAME:
return isImmutableValue(value);
case GETELEM:
case GETPROP:
// There is no information about the locality of object properties.
return false;
case CALL:
return callHasLocalResult(value) || isToStringMethodCall(value);
case TAGGED_TEMPLATELIT:
return callHasLocalResult(value);
case NEW:
return newHasLocalResult(value);
case DELPROP:
case INC:
case DEC:
case CLASS:
case FUNCTION:
case REGEXP:
case EMPTY:
case ARRAYLIT:
case OBJECTLIT:
case TEMPLATELIT:
return true;
case CAST:
return evaluatesToLocalValue(value.getFirstChild());
case SPREAD:
// TODO(johnlenz): remove this case.
case YIELD:
case AWAIT:
// TODO(johnlenz): we can do better for await if we use type information. That is,
// if we know the promise being awaited on is a immutable value type (string, etc)
// we could return true here.
return false;
default:
// Other op force a local value:
// '' + g (a local string)
// x -= g (x is now an local number)
if (isAssignmentOp(value)
|| isSimpleOperator(value)
|| isImmutableValue(value)) {
return true;
}
throw new IllegalStateException(
"Unexpected expression node: " + value + "\n parent:" + value.getParent());
}
}
/**
* @return Whether the provided expression is may evaluate to 'undefined'.
*/
static boolean mayBeUndefined(Node n) {
return !isDefinedValue(n);
}
/**
* @return Whether the provided expression is known not to evaluate to 'undefined'.
*
* Similar to #getKnownValueType only for 'undefined'. This is useful for simplifying
* default value expressions.
*/
static boolean isDefinedValue(Node value) {
switch (value.getToken()) {
case ASSIGN: // Only the assigned value matters here.
case CAST:
case COMMA:
return isDefinedValue(value.getLastChild());
case AND:
case OR:
return isDefinedValue(value.getFirstChild())
&& isDefinedValue(value.getLastChild());
case HOOK:
return isDefinedValue(value.getSecondChild())
&& isDefinedValue(value.getLastChild());
// Assume undefined leaks in this and call results.
case CALL:
case NEW:
case GETELEM:
case GETPROP:
case TAGGED_TEMPLATELIT:
case THIS:
case YIELD:
case AWAIT:
case VOID:
return false;
case DELPROP:
case INC:
case DEC:
case CLASS:
case FUNCTION:
case REGEXP:
case EMPTY:
case ARRAYLIT:
case OBJECTLIT:
case TEMPLATELIT:
case STRING:
case NUMBER:
case NULL:
case TRUE:
case FALSE:
return true;
case TEMPLATELIT_STRING:
return value.getCookedString() != null;
case NAME:
String name = value.getString();
// We assume here that programs don't change the value of the keyword
// undefined to something other than the value undefined.
return "Infinity".equals(name) || "NaN".equals(name);
default:
// Other op force a local value:
// '' + g (a string)
// x -= g (x is now an number)
if (isAssignmentOp(value) || isSimpleOperator(value)) {
return true;
}
throw new IllegalStateException(
"Unexpected expression node: " + value + "\n parent:" + value.getParent());
}
}
/**
* Given the first sibling, this returns the nth
* sibling or null if no such sibling exists.
* This is like "getChildAtIndex" but returns null for non-existent indexes.
*/
private static Node getNthSibling(Node first, int index) {
Node sibling = first;
while (index != 0 && sibling != null) {
sibling = sibling.getNext();
index--;
}
return sibling;
}
/**
* Given the function, this returns the nth
* argument or null if no such parameter exists.
*/
static Node getArgumentForFunction(Node function, int index) {
checkState(function.isFunction());
return getNthSibling(
function.getSecondChild().getFirstChild(), index);
}
/**
* Given the new or call, this returns the nth
* argument of the call or null if no such argument exists.
*/
static Node getArgumentForCallOrNew(Node call, int index) {
checkState(isCallOrNew(call));
return getNthSibling(call.getSecondChild(), index);
}
/**
* Returns whether this is a target of a call or new.
*/
static boolean isInvocationTarget(Node n) {
Node parent = n.getParent();
return parent != null && (isCallOrNew(parent) || parent.isTaggedTemplateLit())
&& parent.getFirstChild() == n;
}
/**
* Returns whether this is a call (including tagged template lits) or new.
*/
static boolean isInvocation(Node n) {
return isCallOrNew(n) || n.isTaggedTemplateLit();
}
static boolean isCallOrNewArgument(Node n) {
Node parent = n.getParent();
return parent != null && isCallOrNew(parent) && parent.getFirstChild() != n;
}
private static boolean isToStringMethodCall(Node call) {
Node getNode = call.getFirstChild();
if (isGet(getNode)) {
Node propNode = getNode.getLastChild();
return propNode.isString() && "toString".equals(propNode.getString());
}
return false;
}
/** Return declared JSDoc type for the given name declaration, or null if none present. */
@Nullable
public static JSTypeExpression getDeclaredTypeExpression(Node declaration) {
checkArgument(declaration.isName() || declaration.isStringKey());
JSDocInfo nameJsdoc = getBestJSDocInfo(declaration);
if (nameJsdoc != null) {
return nameJsdoc.getType();
}
Node parent = declaration.getParent();
if (parent.isRest() || parent.isDefaultValue()) {
parent = parent.getParent();
}
if (parent.isParamList()) {
JSDocInfo functionJsdoc = getBestJSDocInfo(parent.getParent());
if (functionJsdoc != null) {
return functionJsdoc.getParameterType(declaration.getString());
}
}
return null;
}
/** Find the best JSDoc for the given node. */
@Nullable
public static JSDocInfo getBestJSDocInfo(Node n) {
Node jsdocNode = getBestJSDocInfoNode(n);
return jsdocNode == null ? null : jsdocNode.getJSDocInfo();
}
@Nullable
public static Node getBestJSDocInfoNode(Node n) {
if (n.isExprResult()) {
return getBestJSDocInfoNode(n.getFirstChild());
}
JSDocInfo info = n.getJSDocInfo();
if (info == null) {
Node parent = n.getParent();
if (parent == null || n.isExprResult()) {
return null;
}
if (parent.isName()) {
return getBestJSDocInfoNode(parent);
} else if (parent.isAssign()) {
return getBestJSDocInfoNode(parent);
} else if (mayBeObjectLitKey(parent) || parent.isComputedProp()) {
return parent;
} else if ((parent.isFunction() || parent.isClass()) && n == parent.getFirstChild()) {
// n is the NAME node of the function/class.
return getBestJSDocInfoNode(parent);
} else if (NodeUtil.isNameDeclaration(parent) && parent.hasOneChild()) {
return parent;
} else if ((parent.isHook() && parent.getFirstChild() != n)
|| parent.isOr()
|| parent.isAnd()
|| (parent.isComma() && parent.getFirstChild() != n)) {
return getBestJSDocInfoNode(parent);
}
}
return n;
}
/** Find the l-value that the given r-value is being assigned to. */
public static Node getBestLValue(Node n) {
Node parent = n.getParent();
if (isFunctionDeclaration(n) || isClassDeclaration(n)) {
return n.getFirstChild();
} else if (n.isClassMembers()) {
return getBestLValue(parent);
} else if (parent.isName()) {
return parent;
} else if (parent.isAssign()) {
return parent.getFirstChild();
} else if (mayBeObjectLitKey(parent) || parent.isComputedProp()) {
return parent;
} else if ((parent.isHook() && parent.getFirstChild() != n)
|| parent.isOr()
|| parent.isAnd()
|| (parent.isComma() && parent.getFirstChild() != n)) {
return getBestLValue(parent);
} else if (parent.isCast()) {
return getBestLValue(parent);
}
return null;
}
/** Gets the r-value (or initializer) of a node returned by getBestLValue. */
public static Node getRValueOfLValue(Node n) {
Node parent = n.getParent();
switch (parent.getToken()) {
case ASSIGN:
case ASSIGN_BITOR:
case ASSIGN_BITXOR:
case ASSIGN_BITAND:
case ASSIGN_LSH:
case ASSIGN_RSH:
case ASSIGN_URSH:
case ASSIGN_ADD:
case ASSIGN_SUB:
case ASSIGN_MUL:
case ASSIGN_EXPONENT:
case ASSIGN_DIV:
case ASSIGN_MOD:
case DESTRUCTURING_LHS:
return n.getNext();
case VAR:
case LET:
case CONST:
return n.getLastChild();
case OBJECTLIT:
case CLASS_MEMBERS:
return n.getOnlyChild();
case FUNCTION:
case CLASS:
return parent;
default:
break;
}
return null;
}
/** Get the owner of the given l-value node. */
static Node getBestLValueOwner(@Nullable Node lValue) {
if (lValue == null || lValue.getParent() == null) {
return null;
}
if (mayBeObjectLitKey(lValue) || lValue.isComputedProp()) {
return getBestLValue(lValue.getParent());
} else if (isGet(lValue)) {
return lValue.getFirstChild();
}
return null;
}
/** Get the name of the given l-value node. */
public static String getBestLValueName(@Nullable Node lValue) {
if (lValue == null || lValue.getParent() == null) {
return null;
}
if (lValue.getParent().isClassMembers() && !lValue.isComputedProp()) {
String className = NodeUtil.getName(lValue.getGrandparent());
if (className == null) { // Anonymous class
return null;
}
String methodName = lValue.getString();
String maybePrototype = lValue.isStaticMember() ? "." : ".prototype.";
return className + maybePrototype + methodName;
}
// TODO(sdh): Tighten this to simply require !lValue.isQuotedString()
// Could get rid of the isJSIdentifier check, but may need to fix depot.
if (mayBeObjectLitKey(lValue)) {
Node owner = getBestLValue(lValue.getParent());
if (owner != null) {
String ownerName = getBestLValueName(owner);
if (ownerName != null) {
String key = getObjectLitKeyName(lValue);
return TokenStream.isJSIdentifier(key) ? ownerName + "." + key : null;
}
}
return null;
}
return lValue.getQualifiedName();
}
/** Gets the root of a qualified name l-value. */
static Node getBestLValueRoot(@Nullable Node lValue) {
if (lValue == null) {
return null;
}
switch (lValue.getToken()) {
case STRING_KEY:
// NOTE: beware of getBestLValue returning null (or be null-permissive?)
return getBestLValueRoot(NodeUtil.getBestLValue(lValue.getParent()));
case GETPROP:
case GETELEM:
return getBestLValueRoot(lValue.getFirstChild());
case THIS:
case SUPER:
case NAME:
return lValue;
default:
return null;
}
}
/**
* @return true iff the result of the expression is consumed.
*/
static boolean isExpressionResultUsed(Node expr) {
Node parent = expr.getParent();
switch (parent.getToken()) {
case BLOCK:
case EXPR_RESULT:
return false;
case CAST:
return isExpressionResultUsed(parent);
case HOOK:
case AND:
case OR:
return (expr == parent.getFirstChild()) || isExpressionResultUsed(parent);
case COMMA:
Node grandparent = parent.getParent();
if (grandparent.isCall() && parent == grandparent.getFirstChild()) {
// Semantically, a direct call to eval is different from an indirect
// call to an eval. See ECMA-262 S15.1.2.1. So it's OK for the first
// expression to a comma to be a no-op if it's used to indirect
// an eval. This we pretend that this is "used".
if (expr == parent.getFirstChild()
&& parent.hasTwoChildren()
&& expr.getNext().isName()
&& "eval".equals(expr.getNext().getString())) {
return true;
}
}
return (expr == parent.getFirstChild()) ? false : isExpressionResultUsed(parent);
case FOR:
// Only an expression whose result is in the condition part of the
// expression is used.
return (parent.getSecondChild() == expr);
default:
break;
}
return true;
}
/**
* @param n The expression to check.
* @return Whether the expression is unconditionally executed only once in the
* containing execution scope.
*/
static boolean isExecutedExactlyOnce(Node n) {
inspect: do {
Node parent = n.getParent();
switch (parent.getToken()) {
case IF:
case HOOK:
case AND:
case OR:
if (parent.getFirstChild() != n) {
return false;
}
// other ancestors may be conditional
continue inspect;
case FOR:
case FOR_IN:
if (parent.isForIn()) {
if (parent.getSecondChild() != n) {
return false;
}
} else {
if (parent.getFirstChild() != n) {
return false;
}
}
// other ancestors may be conditional
continue inspect;
case WHILE:
case DO:
return false;
case TRY:
// Consider all code under a try/catch to be conditionally executed.
if (!hasFinally(parent) || parent.getLastChild() != n) {
return false;
}
continue inspect;
case CASE:
case DEFAULT_CASE:
return false;
case SCRIPT:
case FUNCTION:
// Done, we've reached the scope root.
break inspect;
default:
break;
}
} while ((n = n.getParent()) != null);
return true;
}
/**
* @return An appropriate AST node for the boolean value.
*/
static Node booleanNode(boolean value) {
return value ? IR.trueNode() : IR.falseNode();
}
/**
* @return An appropriate AST node for the double value.
*/
static Node numberNode(double value, Node srcref) {
Node result;
if (Double.isNaN(value)) {
result = IR.name("NaN");
} else if (value == Double.POSITIVE_INFINITY) {
result = IR.name("Infinity");
} else if (value == Double.NEGATIVE_INFINITY) {
result = IR.neg(IR.name("Infinity"));
} else {
result = IR.number(value);
}
if (srcref != null) {
result.srcrefTree(srcref);
}
return result;
}
static boolean isNaN(Node n) {
return (n.isName() && n.getString().equals("NaN"))
|| (n.getToken() == Token.DIV
&& n.getFirstChild().isNumber()
&& n.getFirstChild().getDouble() == 0
&& n.getLastChild().isNumber()
&& n.getLastChild().getDouble() == 0)
|| n.matchesQualifiedName(NUMBER_NAN);
}
private static final Node NUMBER_NAN = IR.getprop(IR.name("Number"), IR.string("NaN"));
/**
* A change scope does not directly correspond to a language scope but is an internal
* grouping of changes.
*
* @return Whether the node represents a change scope root.
*/
static boolean isChangeScopeRoot(Node n) {
return (n.isScript() || n.isFunction());
}
/**
* @return the change scope root
*/
static Node getEnclosingChangeScopeRoot(Node n) {
while (n != null && !isChangeScopeRoot(n)) {
n = n.getParent();
}
return n;
}
static int countAstSizeUpToLimit(Node n, final int limit) {
// Java doesn't allow accessing mutable local variables from another class.
final int[] wrappedSize = {0};
visitPreOrder(
n,
new Visitor() {
@Override
public void visit(Node n) {
wrappedSize[0]++;
}
},
new Predicate() {
@Override
public boolean apply(Node n) {
return wrappedSize[0] < limit;
}
});
return wrappedSize[0];
}
static int countAstSize(Node n) {
int count = 1;
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
count += countAstSize(c);
}
return count;
}
static JSDocInfo createConstantJsDoc() {
JSDocInfoBuilder builder = new JSDocInfoBuilder(false);
builder.recordConstancy();
return builder.build();
}
static int toInt32(double d) {
int id = (int) d;
if (id == d) {
// This covers -0.0 as well
return id;
}
if (Double.isNaN(d)
|| d == Double.POSITIVE_INFINITY
|| d == Double.NEGATIVE_INFINITY) {
return 0;
}
d = (d >= 0) ? Math.floor(d) : Math.ceil(d);
double two32 = 4294967296.0;
d = d % two32;
// (double)(long)d == d should hold here
long l = (long) d;
// returning (int)d does not work as d can be outside int range
// but the result must always be 32 lower bits of l
return (int) l;
}
static int toUInt32(double d) {
if (Double.isNaN(d) || Double.isInfinite(d) || d == 0) {
return 0;
}
d = Math.signum(d) * Math.floor(Math.abs(d));
double two32 = 4294967296.0;
// this ensures that d is positive
d = ((d % two32) + two32) % two32;
// (double)(long)d == d should hold here
long l = (long) d;
// returning (int)d does not work as d can be outside int range
// but the result must always be 32 lower bits of l
return (int) l;
}
static boolean isGoogModuleCall(Node n) {
if (isExprCall(n)) {
Node target = n.getFirstFirstChild();
return (target.matchesQualifiedName("goog.module"));
}
return false;
}
static boolean isModuleScopeRoot(Node n) {
return n.isModuleBody() || isBundledGoogModuleScopeRoot(n);
}
static boolean isBundledGoogModuleCall(Node n) {
if (!(n.isCall()
&& n.hasTwoChildren()
&& n.getFirstChild().matchesQualifiedName("goog.loadModule"))) {
return false;
}
return n.getParent() != null
&& n.getParent().isExprResult()
&& n.getGrandparent() != null
&& n.getGrandparent().isScript();
}
static boolean isBundledGoogModuleScopeRoot(Node n) {
if (!n.isBlock() || !n.hasChildren() || !isGoogModuleCall(n.getFirstChild())) {
return false;
}
Node function = n.getParent();
if (function == null
|| !function.isFunction()
|| !getFunctionParameters(function).hasOneChild()
|| !getFunctionParameters(function).getFirstChild().matchesQualifiedName("exports")) {
return false;
}
Node call = function.getParent();
if (!call.isCall()
|| !call.hasTwoChildren()
|| !call.getFirstChild().matchesQualifiedName("goog.loadModule")) {
return false;
}
return call.getParent().isExprResult() && call.getGrandparent().isScript();
}
static boolean isGoogModuleDeclareLegacyNamespaceCall(Node n) {
if (isExprCall(n)) {
Node target = n.getFirstFirstChild();
return (target.matchesQualifiedName(googModuleDeclareLegacyNamespace));
}
return false;
}
public static boolean isTopLevel(Node n) {
return n.isScript() || n.isModuleBody();
}
/**
* @return Whether the node is a goog.module file's SCRIPT node.
*/
static boolean isGoogModuleFile(Node n) {
return n.isScript() && n.hasChildren() && n.getFirstChild().isModuleBody()
&& isGoogModuleCall(n.getFirstFirstChild());
}
/**
* @return Whether the node is a SCRIPT node for a goog.module that has a
* declareLegacyNamespace call.
*/
static boolean isLegacyGoogModuleFile(Node n) {
return isGoogModuleFile(n)
&& isGoogModuleDeclareLegacyNamespaceCall(n.getFirstChild().getSecondChild());
}
static boolean isConstructor(Node fnNode) {
if (fnNode == null || !fnNode.isFunction()) {
return false;
}
JSType type = fnNode.getJSType();
JSDocInfo jsDocInfo = getBestJSDocInfo(fnNode);
return (type != null && type.isConstructor())
|| (jsDocInfo != null && jsDocInfo.isConstructor())
|| isEs6Constructor(fnNode);
}
public static boolean isEs6ConstructorMemberFunctionDef(Node memberFunctionDef) {
if (!memberFunctionDef.isMemberFunctionDef()) {
return false; // not a member function at all
}
return memberFunctionDef.getParent().isClassMembers() // is in a class
&& !memberFunctionDef.isStaticMember() // constructors aren't static
&& memberFunctionDef.getString().equals("constructor");
}
public static boolean isEs6Constructor(Node fnNode) {
if (!fnNode.isFunction()) {
return false;
}
Node memberFunctionDef = fnNode.getParent();
return memberFunctionDef != null && isEs6ConstructorMemberFunctionDef(memberFunctionDef);
}
static boolean isGetterOrSetter(Node propNode) {
if (isGetOrSetKey(propNode)) {
return true;
}
if (!propNode.isStringKey() || !propNode.getFirstChild().isFunction()) {
return false;
}
String keyName = propNode.getString();
return keyName.equals("get") || keyName.equals("set");
}
public static boolean isCallTo(Node n, String qualifiedName) {
return n.isCall() && n.getFirstChild().matchesQualifiedName(qualifiedName);
}
/**
* A faster version of {@link #isCallTo(Node, String)}.
*
* @param n node to check if a call
* @param targetMethod the prebuilt AST getprop node that represents the method to check
*/
public static boolean isCallTo(Node n, Node targetMethod) {
if (!n.isCall()) {
return false;
}
return n.getFirstChild().matchesQualifiedName(targetMethod);
}
static ImmutableSet collectExternVariableNames(AbstractCompiler compiler, Node externs) {
ReferenceCollectingCallback externsRefs =
new ReferenceCollectingCallback(
compiler,
ReferenceCollectingCallback.DO_NOTHING_BEHAVIOR,
new Es6SyntacticScopeCreator(compiler));
externsRefs.process(externs);
ImmutableSet.Builder externsNames = ImmutableSet.builder();
for (Var v : externsRefs.getAllSymbols()) {
if (!v.isParam()) {
externsNames.add(v.getName());
}
}
return externsNames.build();
}
/** Recurses through a tree, marking all function nodes as changed. */
static void markNewScopesChanged(Node node, AbstractCompiler compiler) {
if (node.isFunction()) {
compiler.reportChangeToChangeScope(node);
}
for (Node child = node.getFirstChild(); child != null; child = child.getNext()) {
markNewScopesChanged(child, compiler);
}
}
/** Recurses through a tree, marking all function nodes deleted. */
public static void markFunctionsDeleted(Node node, AbstractCompiler compiler) {
if (node.isFunction()) {
compiler.reportFunctionDeleted(node);
}
for (Node child = node.getFirstChild(); child != null; child = child.getNext()) {
markFunctionsDeleted(child, compiler);
}
}
/** Returns the list of scope nodes which are parents of the provided list of scope nodes. */
public static List getParentChangeScopeNodes(List scopeNodes) {
Set parentScopeNodes = new LinkedHashSet<>(scopeNodes);
for (Node scopeNode : scopeNodes) {
parentScopeNodes.add(getEnclosingChangeScopeRoot(scopeNode));
}
return new ArrayList<>(parentScopeNodes);
}
/**
* Removes any scope nodes from the provided list that are nested within some other scope node
* also in the list. Returns the modified list.
*/
public static List removeNestedChangeScopeNodes(List scopeNodes) {
Set uniqueScopeNodes = new LinkedHashSet<>(scopeNodes);
for (Node scopeNode : scopeNodes) {
for (Node ancestor = scopeNode.getParent();
ancestor != null;
ancestor = ancestor.getParent()) {
if (isChangeScopeRoot(ancestor) && uniqueScopeNodes.contains(ancestor)) {
uniqueScopeNodes.remove(scopeNode);
break;
}
}
}
return new ArrayList<>(uniqueScopeNodes);
}
static Iterable getInvocationArgsAsIterable(Node invocation){
if (invocation.isTaggedTemplateLit()) {
return new TemplateArgsIterable(invocation.getLastChild());
} else {
checkState(isCallOrNew(invocation), invocation);
return invocation.hasOneChild() ? ImmutableList.of() : invocation.getSecondChild().siblings();
}
}
/**
* Returns the number of arguments in this invocation. For template literals it takes into
* account the implicit first argument of ITemplateArray
*/
static int getInvocationArgsCount(Node invocation) {
if (invocation.isTaggedTemplateLit()) {
Iterable args = new TemplateArgsIterable(invocation.getLastChild());
return Iterables.size(args) + 1;
} else {
return invocation.getChildCount() - 1;
}
}
/**
* Represents an iterable of the children of templatelit_sub nodes of a template lit node
* This iterable will skip over the String children of the template lit node.
*/
private static final class TemplateArgsIterable implements Iterable{
private final Node templateLit;
TemplateArgsIterable(Node templateLit) {
checkState(templateLit.isTemplateLit());
this.templateLit = templateLit;
}
@Override
public Iterator iterator() {
return new AbstractIterator() {
@Nullable private Node nextChild = templateLit.getFirstChild();
@Override
protected Node computeNext() {
while (nextChild != null && !nextChild.isTemplateLitSub()) {
nextChild = nextChild.getNext();
}
if (nextChild == null) {
return endOfData();
} else {
Node result = nextChild.getFirstChild();
nextChild = nextChild.getNext();
return result;
}
}
};
}
}
/**
* Records a mapping of names to vars of everything reachable in a function. Should only be called
* with a function scope. Does not enter new control flow areas aka embedded functions.
*
* @param nameVarMap an empty map that gets populated with the keys being variable names and
* values being variable objects
* @param orderedVars an empty list that gets populated with variable objects in the order that
* they appear in the fn
*/
static void getAllVarsDeclaredInFunction(
final Map nameVarMap,
final List orderedVars,
AbstractCompiler compiler,
ScopeCreator scopeCreator,
final Scope scope) {
checkState(nameVarMap.isEmpty());
checkState(orderedVars.isEmpty());
checkState(scope.isFunctionScope(), scope);
ScopedCallback finder =
new ScopedCallback() {
@Override
public void enterScope(NodeTraversal t) {
Scope currentScope = t.getScope();
for (Var v : currentScope.getVarIterable()) {
nameVarMap.put(v.getName(), v);
orderedVars.add(v);
}
}
@Override
public void exitScope(NodeTraversal t) {}
@Override
public final boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
// Don't enter any new functions
return !n.isFunction() || n == scope.getRootNode();
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {}
};
NodeTraversal t = new NodeTraversal(compiler, finder, scopeCreator);
t.traverseAtScope(scope);
}
/** Returns true if the node is a property of an object literal. */
public static boolean isObjLitProperty(Node node) {
return node.isStringKey()
|| node.isGetterDef()
|| node.isSetterDef()
|| node.isMemberFunctionDef()
|| node.isComputedProp();
}
/** @return Whether the node represents the return value of a blockless Arrow function */
public static boolean isBlocklessArrowFunctionResult(Node n) {
Node parent = n.getParent();
return parent != null && parent.isFunction() && n == parent.getLastChild() && !n.isBlock();
}
/**
* Returns a script node's FeatureSet, which is set at parse-time. This may not be up-to-date
* as passes can add/remove features from a script node's descendants.
*
* The feature set will be null if the script node was created artificially or if the parser
* didn't detect any interesting features.
*/
@Nullable
static FeatureSet getFeatureSetOfScript(Node scriptNode) {
checkState(scriptNode.isScript(), scriptNode);
return (FeatureSet) scriptNode.getProp(Node.FEATURE_SET);
}
/** Adds the given features to a SCRIPT node's FeatureSet property. */
static void addFeatureToScript(Node scriptNode, Feature feature) {
checkState(scriptNode.isScript(), scriptNode);
FeatureSet currentFeatures = getFeatureSetOfScript(scriptNode);
FeatureSet newFeatures =
currentFeatures != null
? currentFeatures.with(feature)
: FeatureSet.BARE_MINIMUM.with(feature);
scriptNode.putProp(Node.FEATURE_SET, newFeatures);
}
}