com.google.javascript.jscomp.RemoveTypes Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of closure-compiler Show documentation

Closure Compiler is a JavaScript optimizing compiler. It parses your JavaScript, analyzes it, removes dead code and rewrites and minimizes what's left. It also checks syntax, variable references, and types, and warns about common JavaScript pitfalls. It is used in many of Google's JavaScript apps, including Gmail, Google Web Search, Google Maps, and Google Docs.

There is a newer version: v20240317

Show newest version

/*
 * Copyright 2020 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 com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;

/**
 * Pass to remove from the AST types and type-based information from typechecking.
 *
 * Eventually, we anticipate this pass to run at the beginning of optimizations, and leave a
 * representation of the types as needed for optimizations on the AST.
 */
final class RemoveTypes implements CompilerPass {
  private final AbstractCompiler compiler;

  RemoveTypes(AbstractCompiler compiler) {
    this.compiler = compiler;
  }

  private static class RemoveTypesFromAst extends AbstractPostOrderCallback {
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      n.setJSType(null);
      n.setJSTypeBeforeCast(null);
      n.setTypedefTypeProp(null);
      n.setDeclaredTypeExpression(null);
      JSDocInfo jsdoc = n.getJSDocInfo();
      if (jsdoc != null && jsdoc.getLicense() == null) {
        // Can license jsdocs also contain type declarations?
        // If so, they should be removed here.
        n.setJSDocInfo(null);
      }
    }
  }

  @Override
  public void process(Node externs, Node root) {
    Node externsAndJsRoot = root.getParent();
    NodeTraversal.traverse(compiler, externsAndJsRoot, new RemoveTypesFromAst());
    compiler.clearJSTypeRegistry();
  }
}