com.google.javascript.jscomp.TranspilationPasses Maven / Gradle / Ivy
/*
* Copyright 2016 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.javascript.jscomp.parsing.parser.FeatureSet.ES2018;
import static com.google.javascript.jscomp.parsing.parser.FeatureSet.ES6;
import static com.google.javascript.jscomp.parsing.parser.FeatureSet.ES7;
import static com.google.javascript.jscomp.parsing.parser.FeatureSet.ES8;
import static com.google.javascript.jscomp.parsing.parser.FeatureSet.ES_NEXT;
import com.google.javascript.jscomp.Es6RewriteDestructuring.ObjectDestructuringRewriteMode;
import com.google.javascript.jscomp.NodeTraversal.Callback;
import com.google.javascript.jscomp.PassFactory.HotSwapPassFactory;
import com.google.javascript.jscomp.parsing.parser.FeatureSet;
import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
import com.google.javascript.rhino.Node;
import java.util.List;
/**
* Provides a single place to manage transpilation passes.
*/
public class TranspilationPasses {
private TranspilationPasses() {}
public static void addEs6ModulePass(
List passes,
final PreprocessorSymbolTable.CachedInstanceFactory preprocessorTableFactory) {
passes.add(
new HotSwapPassFactory("es6RewriteModule") {
@Override
protected HotSwapCompilerPass create(AbstractCompiler compiler) {
preprocessorTableFactory.maybeInitialize(compiler);
return new Es6RewriteModules(
compiler,
compiler.getModuleMetadataMap(),
compiler.getModuleMap(),
preprocessorTableFactory.getInstanceOrNull());
}
@Override
protected FeatureSet featureSet() {
return ES_NEXT;
}
});
}
public static void addPreTypecheckTranspilationPasses(
List passes, CompilerOptions options) {
// TODO(bradfordcsmith): Rename this since it isn't just libraries for ES6 features anymore.
// Inject runtime libraries needed for the transpilation we will have to do.
passes.add(es6InjectRuntimeLibraries);
}
public static void addEs6ModuleToCjsPass(List passes) {
passes.add(es6RewriteModuleToCjs);
}
public static void addEs6RewriteImportPathPass(List passes) {
passes.add(es6RelativizeImportPaths);
}
/** Adds transpilation passes that should run after all checks are done. */
public static void addPostCheckTranspilationPasses(
List passes, CompilerOptions options) {
if (options.needsTranspilationFrom(FeatureSet.ES_NEXT)) {
passes.add(rewriteCatchWithNoBinding);
}
if (options.needsTranspilationFrom(ES2018)) {
passes.add(rewriteAsyncIteration);
passes.add(rewriteObjectSpread);
}
if (options.needsTranspilationFrom(ES8)) {
// Trailing commas in parameter lists are flagged as present by the parser,
// but never actually represented in the AST.
// The only thing we need to do is mark them as not present in the AST.
passes.add(
createFeatureRemovalPass(
"markTrailingCommasInParameterListsRemoved", Feature.TRAILING_COMMA_IN_PARAM_LIST));
passes.add(rewriteAsyncFunctions);
}
if (options.needsTranspilationFrom(ES7)) {
passes.add(rewriteExponentialOperator);
}
if (options.needsTranspilationFrom(ES6)) {
// TODO(b/73387406): Move passes here as typechecking & other check passes are updated to cope
// with the features they transpile and as the passes themselves are updated to propagate type
// information to the transpiled code.
// Binary and octal literals are effectively transpiled by the parser.
// There's no transpilation we can do for the new regexp flags.
passes.add(
createFeatureRemovalPass(
"markEs6FeaturesNotRequiringTranspilationAsRemoved",
Feature.BINARY_LITERALS,
Feature.OCTAL_LITERALS,
Feature.REGEXP_FLAG_U,
Feature.REGEXP_FLAG_Y));
passes.add(es6NormalizeShorthandProperties);
passes.add(es6RewriteClassExtends);
passes.add(es6ConvertSuper);
passes.add(es6RenameVariablesInParamLists);
passes.add(es6SplitVariableDeclarations);
passes.add(
getEs6RewriteDestructuring(ObjectDestructuringRewriteMode.REWRITE_ALL_OBJECT_PATTERNS));
passes.add(es6RewriteArrowFunction);
passes.add(es6ExtractClasses);
passes.add(es6RewriteClass);
passes.add(es6RewriteRestAndSpread);
passes.add(lateConvertEs6ToEs3);
passes.add(es6ForOf);
passes.add(rewriteBlockScopedFunctionDeclaration);
passes.add(rewriteBlockScopedDeclaration);
passes.add(rewriteGenerators);
passes.add(es6ConvertSuperConstructorCalls);
} else if (options.needsTranspilationOf(Feature.OBJECT_PATTERN_REST)) {
passes.add(es6RenameVariablesInParamLists);
passes.add(es6SplitVariableDeclarations);
passes.add(getEs6RewriteDestructuring(ObjectDestructuringRewriteMode.REWRITE_OBJECT_REST));
}
}
/**
* Adds the pass to inject ES6 polyfills, which goes after the late ES6 passes.
*/
public static void addRewritePolyfillPass(List passes) {
passes.add(rewritePolyfills);
}
/** Rewrites ES6 modules */
private static final PassFactory es6RewriteModuleToCjs =
new PassFactory("es6RewriteModuleToCjs", true) {
@Override
protected CompilerPass create(AbstractCompiler compiler) {
return new Es6RewriteModulesToCommonJsModules(compiler);
}
@Override
protected FeatureSet featureSet() {
return FeatureSet.latest();
}
};
/** Rewrites ES6 modules import paths to be browser compliant */
private static final PassFactory es6RelativizeImportPaths =
new PassFactory("es6RelativizeImportPaths", true) {
@Override
protected CompilerPass create(AbstractCompiler compiler) {
return new Es6RelativizeImportPaths(compiler);
}
@Override
protected FeatureSet featureSet() {
return FeatureSet.latest();
}
};
private static final PassFactory rewriteAsyncFunctions =
new HotSwapPassFactory("rewriteAsyncFunctions") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new RewriteAsyncFunctions.Builder(compiler)
// If ES6 classes will not be transpiled away later,
// transpile away property references that use `super` in async functions.
// See explanation in RewriteAsyncFunctions.
.rewriteSuperPropertyReferencesWithoutSuper(
!compiler.getOptions().needsTranspilationFrom(FeatureSet.ES6))
.build();
}
@Override
protected FeatureSet featureSet() {
return ES_NEXT;
}
};
private static final PassFactory rewriteAsyncIteration =
new HotSwapPassFactory("rewriteAsyncIteration") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new RewriteAsyncIteration.Builder(compiler)
// If ES6 classes will not be transpiled away later,
// transpile away property references that use `super` in async iteration.
// See explanation in RewriteAsyncIteration.
.rewriteSuperPropertyReferencesWithoutSuper(
!compiler.getOptions().needsTranspilationFrom(FeatureSet.ES6))
.build();
}
@Override
protected FeatureSet featureSet() {
return ES_NEXT;
}
};
private static final PassFactory rewriteObjectSpread =
new HotSwapPassFactory("rewriteObjectSpread") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new RewriteObjectSpread(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES_NEXT;
}
};
private static final PassFactory rewriteCatchWithNoBinding =
new HotSwapPassFactory("rewriteCatchWithNoBinding") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new RewriteCatchWithNoBinding(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES_NEXT;
}
};
private static final PassFactory rewriteExponentialOperator =
new HotSwapPassFactory("rewriteExponentialOperator") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es7RewriteExponentialOperator(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES2018;
}
};
private static final HotSwapPassFactory es6NormalizeShorthandProperties =
new HotSwapPassFactory("es6NormalizeShorthandProperties") {
@Override
protected HotSwapCompilerPass create(AbstractCompiler compiler) {
return new Es6NormalizeShorthandProperties(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES2018;
}
};
static final HotSwapPassFactory es6RewriteClassExtends =
new HotSwapPassFactory(PassNames.ES6_REWRITE_CLASS_EXTENDS) {
@Override
protected HotSwapCompilerPass create(AbstractCompiler compiler) {
return new Es6RewriteClassExtendsExpressions(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES2018;
}
};
static final HotSwapPassFactory es6ExtractClasses =
new HotSwapPassFactory(PassNames.ES6_EXTRACT_CLASSES) {
@Override
protected HotSwapCompilerPass create(AbstractCompiler compiler) {
return new Es6ExtractClasses(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES8;
}
};
static final HotSwapPassFactory es6RewriteClass =
new HotSwapPassFactory("Es6RewriteClass") {
@Override
protected HotSwapCompilerPass create(AbstractCompiler compiler) {
return new Es6RewriteClass(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES8;
}
};
static final HotSwapPassFactory getEs6RewriteDestructuring(
ObjectDestructuringRewriteMode rewriteMode) {
return new HotSwapPassFactory("Es6RewriteDestructuring") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6RewriteDestructuring.Builder(compiler)
.setDestructuringRewriteMode(rewriteMode)
.build();
}
@Override
protected FeatureSet featureSet() {
return ES2018;
}
};
}
static final HotSwapPassFactory es6RenameVariablesInParamLists =
new HotSwapPassFactory("Es6RenameVariablesInParamLists") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6RenameVariablesInParamLists(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES2018;
}
};
static final HotSwapPassFactory es6RewriteArrowFunction =
new HotSwapPassFactory("Es6RewriteArrowFunction") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6RewriteArrowFunction(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES8;
}
};
static final HotSwapPassFactory rewritePolyfills =
new HotSwapPassFactory("RewritePolyfills") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new RewritePolyfills(compiler);
}
@Override
protected FeatureSet featureSet() {
return FeatureSet.latest();
}
};
static final HotSwapPassFactory es6SplitVariableDeclarations =
new HotSwapPassFactory("Es6SplitVariableDeclarations") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6SplitVariableDeclarations(compiler);
}
@Override
protected FeatureSet featureSet() {
return FeatureSet.latest();
}
};
static final HotSwapPassFactory es6ConvertSuperConstructorCalls =
new HotSwapPassFactory("es6ConvertSuperConstructorCalls") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6ConvertSuperConstructorCalls(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES8;
}
};
static final HotSwapPassFactory es6ConvertSuper =
new HotSwapPassFactory("es6ConvertSuper") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6ConvertSuper(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES2018;
}
};
/** Injects runtime library code needed for transpiled ES6 code. */
static final HotSwapPassFactory es6InjectRuntimeLibraries =
new HotSwapPassFactory("es6InjectRuntimeLibraries") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6InjectRuntimeLibraries(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES_NEXT;
}
};
/** Transpiles REST parameters and SPREAD in both array literals and function calls. */
static final HotSwapPassFactory es6RewriteRestAndSpread =
new HotSwapPassFactory("es6RewriteRestAndSpread") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6RewriteRestAndSpread(compiler);
}
@Override
protected FeatureSet featureSet() {
return FeatureSet.latest();
}
};
/**
* Does the main ES6 to ES3 conversion. There are a few other passes which run before this one, to
* convert constructs which are not converted by this pass. This pass can run after NTI
*/
static final HotSwapPassFactory lateConvertEs6ToEs3 =
new HotSwapPassFactory("lateConvertEs6") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new LateEs6ToEs3Converter(compiler);
}
@Override
protected FeatureSet featureSet() {
return FeatureSet.latest();
}
};
static final HotSwapPassFactory es6ForOf =
new HotSwapPassFactory("es6ForOf") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6ForOfConverter(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES8;
}
};
static final HotSwapPassFactory rewriteBlockScopedFunctionDeclaration =
new HotSwapPassFactory("Es6RewriteBlockScopedFunctionDeclaration") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6RewriteBlockScopedFunctionDeclaration(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES8;
}
};
static final HotSwapPassFactory rewriteBlockScopedDeclaration =
new HotSwapPassFactory("Es6RewriteBlockScopedDeclaration") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6RewriteBlockScopedDeclaration(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES8;
}
};
static final HotSwapPassFactory rewriteGenerators =
new HotSwapPassFactory("rewriteGenerators") {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new Es6RewriteGenerators(compiler);
}
@Override
protected FeatureSet featureSet() {
return ES8;
}
};
/**
* @param script The SCRIPT node representing a JS file
* @return If the file has any features which are part of ES6 or higher but not part of ES5.
*/
static boolean isScriptEs6OrHigher(Node script) {
FeatureSet features = NodeUtil.getFeatureSetOfScript(script);
return features != null && !FeatureSet.ES5.contains(features);
}
/**
* @param script The SCRIPT node representing a JS file
* @return If the file has any features not in {@code supportedFeatures}
*/
static boolean doesScriptHaveUnsupportedFeatures(Node script, FeatureSet supportedFeatures) {
FeatureSet features = NodeUtil.getFeatureSetOfScript(script);
return features != null && !supportedFeatures.contains(features);
}
/**
* Process transpilations if the input language needs transpilation from certain features, on any
* JS file that has features not present in the compiler's output language mode.
*
* @param compiler An AbstractCompiler
* @param combinedRoot The combined root for all JS files.
* @param featureSet The features which this pass helps transpile.
* @param callbacks The callbacks that should be invoked if a file has ES6 features.
*/
static void processTranspile(
AbstractCompiler compiler, Node combinedRoot, FeatureSet featureSet, Callback... callbacks) {
if (compiler.getOptions().needsTranspilationFrom(featureSet)) {
FeatureSet languageOutFeatures = compiler.getOptions().getOutputFeatureSet();
for (Node singleRoot : combinedRoot.children()) {
// Only run the transpilation if this file has features not in the compiler's target output
// language. For example, if this file is purely ES6 and the output language is ES6, don't
// run any transpilation passes on it.
// TODO(lharker): We could save time by being more selective about what files we transpile.
// e.g. if a file has async functions but not `**`, don't run `**` transpilation on it.
// Right now we know what features were in a file at parse time, but not what features were
// added to that file by other transpilation passes.
if (doesScriptHaveUnsupportedFeatures(singleRoot, languageOutFeatures)) {
for (Callback callback : callbacks) {
singleRoot.putBooleanProp(Node.TRANSPILED, true);
NodeTraversal.traverse(compiler, singleRoot, callback);
}
}
}
}
}
/**
* Hot-swap ES6+ transpilations if the input language needs transpilation from certain features,
* on any JS file that has features not present in the compiler's output language mode.
*
* @param compiler An AbstractCompiler
* @param scriptRoot The SCRIPT root for the JS file.
* @param featureSet The features which this pass helps transpile.
* @param callbacks The callbacks that should be invoked if the file has ES6 features.
*/
static void hotSwapTranspile(
AbstractCompiler compiler, Node scriptRoot, FeatureSet featureSet, Callback... callbacks) {
if (compiler.getOptions().needsTranspilationFrom(featureSet)) {
FeatureSet languageOutFeatures = compiler.getOptions().getOutputFeatureSet();
if (doesScriptHaveUnsupportedFeatures(scriptRoot, languageOutFeatures)) {
for (Callback callback : callbacks) {
scriptRoot.putBooleanProp(Node.TRANSPILED, true);
NodeTraversal.traverse(compiler, scriptRoot, callback);
}
}
}
}
static void maybeMarkFeaturesAsTranspiledAway(
AbstractCompiler compiler, FeatureSet transpiledFeatures) {
// We don't bother to do this if the compiler has halting errors, which avoids unnecessary
// warnings from AstValidator warning that the features are still there.
if (!compiler.hasHaltingErrors()) {
compiler.setFeatureSet(compiler.getFeatureSet().without(transpiledFeatures));
}
}
static void maybeMarkFeaturesAsTranspiledAway(
AbstractCompiler compiler, Feature transpiledFeature, Feature... moreTranspiledFeatures) {
if (!compiler.hasHaltingErrors()) {
compiler.setFeatureSet(
compiler.getFeatureSet().without(transpiledFeature, moreTranspiledFeatures));
}
}
/**
* Returns a pass that just removes features from the AST FeatureSet.
*
* Doing this indicates that the AST no longer contains uses of the features, or that they are
* no longer of concern for some other reason.
*/
private static HotSwapPassFactory createFeatureRemovalPass(
String passName, final Feature featureToRemove, final Feature... moreFeaturesToRemove) {
return new HotSwapPassFactory(passName) {
@Override
protected HotSwapCompilerPass create(final AbstractCompiler compiler) {
return new HotSwapCompilerPass() {
@Override
public void hotSwapScript(Node scriptRoot, Node originalRoot) {
maybeMarkFeaturesAsTranspiledAway(compiler, featureToRemove, moreFeaturesToRemove);
}
@Override
public void process(Node externs, Node root) {
maybeMarkFeaturesAsTranspiledAway(compiler, featureToRemove, moreFeaturesToRemove);
}
};
}
@Override
protected FeatureSet featureSet() {
return FeatureSet.latest();
}
};
}
}