com.google.javascript.jscomp.Es6TemplateLiterals Maven / Gradle / Ivy
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/*
* Copyright 2014 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.checkState;
import static com.google.javascript.jscomp.Es6ToEs3Util.createGenericType;
import static com.google.javascript.jscomp.Es6ToEs3Util.createType;
import static com.google.javascript.jscomp.Es6ToEs3Util.withType;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.jstype.JSType;
import com.google.javascript.rhino.jstype.JSTypeNative;
import com.google.javascript.rhino.jstype.JSTypeRegistry;
/**
* Helper class for transpiling ES6 template literals.
*/
class Es6TemplateLiterals {
private static final String TEMPLATELIT_VAR = "$jscomp$templatelit$";
private final AstFactory astFactory;
private final AbstractCompiler compiler;
private final JSTypeRegistry registry;
Es6TemplateLiterals(AbstractCompiler compiler) {
this.compiler = compiler;
this.astFactory = compiler.createAstFactory();
this.registry = compiler.getTypeRegistry();
}
/**
* Converts `${a} b ${c} d ${e}` to (a + " b " + c + " d " + e)
*
* @param n A TEMPLATELIT node that is not prefixed with a tag
*/
void visitTemplateLiteral(NodeTraversal t, Node n) {
int length = n.getChildCount();
if (length == 0) {
n.replaceWith(astFactory.createString("\"\""));
} else {
Node first = n.removeFirstChild();
checkState(first.isTemplateLitString() && first.getCookedString() != null);
Node firstStr = astFactory.createString(first.getCookedString());
if (length == 1) {
n.replaceWith(firstStr);
} else {
// Add the first string with the first substitution expression
Node add =
withType(IR.add(firstStr, n.removeFirstChild().removeFirstChild()), n.getJSType());
// Process the rest of the template literal
for (int i = 2; i < length; i++) {
Node child = n.removeFirstChild();
if (child.isTemplateLitString()) {
checkState(child.getCookedString() != null);
if (child.getCookedString().isEmpty()) {
continue;
} else if (i == 2 && first.getCookedString().isEmpty()) {
// So that `${hello} world` gets translated into (hello + " world")
// instead of ("" + hello + " world").
add = add.getSecondChild().detach();
}
}
add =
withType(
IR.add(
add,
child.isTemplateLitString()
? astFactory.createString(child.getCookedString())
: child.removeFirstChild()),
n.getJSType());
}
n.replaceWith(add.useSourceInfoIfMissingFromForTree(n));
}
}
t.reportCodeChange();
}
/**
* Converts tag`a\tb${bar}` to:
*
*
* // A global (module) scoped variable
* var $jscomp$templatelit$0 = ["a\tb"]; // cooked string array
* $jscomp$templatelit$0.raw = ["a\\tb"]; // raw string array
* ...
* // A call to the tagging function
* tag($jscomp$templatelit$0, bar);
*
*
*
See template_literal_test.js for more examples.
*
* @param n A TAGGED_TEMPLATELIT node
*/
void visitTaggedTemplateLiteral(NodeTraversal t, Node n, boolean addTypes) {
JSType stringType = createType(addTypes, registry, JSTypeNative.STRING_TYPE);
JSType arrayType = createGenericType(addTypes, registry, JSTypeNative.ARRAY_TYPE, stringType);
JSType templateArrayType =
createType(addTypes, registry, JSTypeNative.I_TEMPLATE_ARRAY_TYPE);
Node templateLit = n.getLastChild();
Node cooked = createCookedStringArray(templateLit, templateArrayType);
Node siteObject = withType(cooked, templateArrayType);
// Create a variable representing the template literal.
Node callsiteId =
astFactory.createName(
TEMPLATELIT_VAR + compiler.getUniqueNameIdSupplier().get(), templateArrayType);
Node var = IR.var(callsiteId, siteObject).useSourceInfoIfMissingFromForTree(n);
Node script = NodeUtil.getEnclosingScript(n);
script.addChildToFront(var);
t.reportCodeChange(var);
// Define the "raw" property on the introduced variable.
Node defineRaw;
if (cookedAndRawStringsSame(templateLit)) {
// The cooked and raw versions of the array are the same, so just call slice() on the
// cooked array at runtime to make the raw array a copy of the cooked array.
defineRaw =
IR.exprResult(
astFactory.createAssign(
astFactory.createGetProp(callsiteId.cloneNode(), "raw"),
astFactory.createCall(
astFactory.createGetProp(callsiteId.cloneNode(), "slice"))))
.useSourceInfoIfMissingFromForTree(n);
} else {
// The raw string array is different, so we need to construct it.
Node raw = createRawStringArray(templateLit, arrayType);
defineRaw =
IR.exprResult(
astFactory.createAssign(
astFactory.createGetProp(callsiteId.cloneNode(), "raw"), raw))
.useSourceInfoIfMissingFromForTree(n);
}
script.addChildAfter(defineRaw, var);
// Generate the call expression.
Node call = withType(IR.call(n.removeFirstChild(), callsiteId.cloneNode()), n.getJSType());
for (Node child = templateLit.getFirstChild(); child != null; child = child.getNext()) {
if (!child.isTemplateLitString()) {
call.addChildToBack(child.removeFirstChild());
}
}
call.useSourceInfoIfMissingFromForTree(templateLit);
call.putBooleanProp(Node.FREE_CALL, !call.getFirstChild().isGetProp());
n.replaceWith(call);
t.reportCodeChange();
}
private Node createRawStringArray(Node n, JSType arrayType) {
Node array = withType(IR.arraylit(), arrayType);
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
if (child.isTemplateLitString()) {
array.addChildToBack(astFactory.createString(child.getRawString()));
}
}
return array;
}
private Node createCookedStringArray(Node n, JSType templateArrayType) {
Node array = withType(IR.arraylit(), templateArrayType);
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
if (child.isTemplateLitString()) {
if (child.getCookedString() != null) {
array.addChildToBack(astFactory.createString(child.getCookedString()));
} else {
// undefined cooked string due to exception in template escapes
array.addChildToBack(astFactory.createVoid(astFactory.createNumber(0)));
}
}
}
return array;
}
private static boolean cookedAndRawStringsSame(Node n) {
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
if (!child.isTemplateLitString()) {
continue;
}
// getCookedString() returns null when the template literal has an illegal escape sequence.
if (child.getCookedString() == null
|| !child.getCookedString().equals(child.getRawString())) {
return false;
}
}
return true;
}
}