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

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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.

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/*
 * 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.parsing.parser.FeatureSet;
import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
import com.google.javascript.rhino.Node;

/** Warns at any usage of Dynamic Import expressions that they are unable to be transpiled. */
public class ForbidDynamicImportUsage implements CompilerPass, NodeTraversal.Callback {
  private final AbstractCompiler compiler;

  static final DiagnosticType DYNAMIC_IMPORT_USAGE =
      DiagnosticType.error(
          "JSC_DYNAMIC_IMPORT_USAGE", "Dynamic import expressions cannot be transpiled.");

  public ForbidDynamicImportUsage(AbstractCompiler compiler) {
    this.compiler = compiler;
  }

  @Override
  public void process(Node externs, Node root) {
    NodeTraversal.traverse(compiler, root, this);
  }

  @Override
  public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
    if (n.isScript()) {
      // We only want to traverse scripts that contain dynamic imports, so we can generate error
      // messages that point to them.
      return getFeatureSetOfScript(n).contains(Feature.DYNAMIC_IMPORT);
    } else {
      return true;
    }
  }

  private FeatureSet getFeatureSetOfScript(Node n) {
    final FeatureSet featureSet = NodeUtil.getFeatureSetOfScript(n);
    return (featureSet == null) ? FeatureSet.BARE_MINIMUM : featureSet;
  }

  @Override
  public void visit(NodeTraversal t, Node n, Node parent) {
    switch (n.getToken()) {
      case DYNAMIC_IMPORT:
        t.report(n, DYNAMIC_IMPORT_USAGE);
        break;
      default:
        break;
    }
  }
}