com.google.javascript.jscomp.gwt.client.Es6ClassConverterJsDocHelper 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 2019 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.gwt.client;

import com.google.common.base.Strings;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.regexp.shared.RegExp;
import com.google.javascript.jscomp.JSDocInfoPrinter;
import com.google.javascript.jscomp.parsing.Config;
import com.google.javascript.jscomp.parsing.Config.JsDocParsing;
import com.google.javascript.jscomp.parsing.Config.LanguageMode;
import com.google.javascript.jscomp.parsing.JsDocInfoParser;
import com.google.javascript.jscomp.parsing.JsDocTokenStream;
import com.google.javascript.rhino.ErrorReporter;
import com.google.javascript.rhino.JSDocInfo;
import jsinterop.annotations.JsMethod;

/**
 * Utilities to parse JS doc and assist in upgrade ES5 to ES6 classes where JS Doc must be split
 * into class and constructor comments.
 */
final class Es6ClassConverterJsDocHelper implements EntryPoint {

  private Es6ClassConverterJsDocHelper() {}

  @Override
  public void onModuleLoad() {
    exportCode();
  }

  private native void exportCode() /*-{
    var getClassJsDoc = $entry(@com.google.javascript.jscomp.gwt.client.Es6ClassConverterJsDocHelper::getClassJsDoc(*));
    var getConstructorJsDoc = $entry(@com.google.javascript.jscomp.gwt.client.Es6ClassConverterJsDocHelper::getConstructorJsDoc(*));
    if (typeof module !== 'undefined' && module.exports) {
      module.exports.getClassJsDoc = getClassJsDoc;
      module.exports.getConstructorJsDoc = getConstructorJsDoc;
    }
  }-*/;

  /**
   * Gets JS Doc that should be retained on a class. Used to upgrade ES5 to ES6 classes and separate
   * class from constructor comments.
   */
  @JsMethod(name = "getClassJsDoc", namespace = "jscomp")
  public static String getClassJsDoc(String jsDoc) {
    if (Strings.isNullOrEmpty(jsDoc)) {
      return null;
    }
    Config config =
        Config.builder()
            .setLanguageMode(LanguageMode.ECMASCRIPT3)
            .setStrictMode(Config.StrictMode.SLOPPY)
            .setJsDocParsingMode(JsDocParsing.INCLUDE_DESCRIPTIONS_WITH_WHITESPACE)
            .build();
    JsDocInfoParser parser =
        new JsDocInfoParser(
            // Stream expects us to remove the leading /**
            new JsDocTokenStream(jsDoc.substring(3)),
            jsDoc,
            0,
            null,
            config,
            ErrorReporter.NULL_INSTANCE);
    parser.parse();
    JSDocInfo parsed = parser.retrieveAndResetParsedJSDocInfo();
    JSDocInfo classComments = parsed.cloneClassDoc();
    JSDocInfoPrinter printer =
        new JSDocInfoPrinter(/* useOriginalName= */ true, /* printDesc= */ true);
    String comment = printer.print(classComments);
    // Don't return empty comments, return null instead.
    if (comment == null || RegExp.compile("\\s*/\\*\\*\\s*\\*/\\s*").test(comment)) {
      return null;
    }
    return comment.trim();
  }

  /**
   * Gets JS Doc that should be moved to a constructor. Used to upgrade ES5 to ES6 classes and
   * separate class from constructor comments.
   */
  @JsMethod(name = "getConstructorJsDoc", namespace = "jscomp")
  public static String getConstructorJsDoc(String jsDoc) {
    if (Strings.isNullOrEmpty(jsDoc)) {
      return null;
    }
    Config config =
        Config.builder()
            .setLanguageMode(LanguageMode.ECMASCRIPT3)
            .setStrictMode(Config.StrictMode.SLOPPY)
            .setJsDocParsingMode(JsDocParsing.INCLUDE_DESCRIPTIONS_WITH_WHITESPACE)
            .build();
    JsDocInfoParser parser =
        new JsDocInfoParser(
            // Stream expects us to remove the leading /**
            new JsDocTokenStream(jsDoc.substring(3)),
            jsDoc,
            0,
            null,
            config,
            ErrorReporter.NULL_INSTANCE);
    parser.parse();
    JSDocInfo parsed = parser.retrieveAndResetParsedJSDocInfo();
    JSDocInfo params = parsed.cloneConstructorDoc();
    if (parsed.getParameterNames().isEmpty() && parsed.getSuppressions().isEmpty()) {
      return null;
    }
    JSDocInfoPrinter printer =
        new JSDocInfoPrinter(/* useOriginalName= */ true, /* printDesc= */ true);
    return printer.print(params).trim();
  }
}