google-closure-compiler/lib/node/index.js

Check, compile, optimize and compress Javascript with Closure-Compiler

/*
 * Copyright 2015 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.
 */

/**
 * @fileoverview Low level class for calling the closure-compiler jar
 * from nodejs
 *
 * @author Chad Killingsworth (chadkillingsworth@gmail.com)
 */
import {spawn} from 'node:child_process';
import compilerPath from 'google-closure-compiler-java';

/**
 * @type {string}
 */
export const javaPath = 'java';

export default class Compiler {
  /**
   * @param {Object<string,string|boolean>|Array<string>} args
   * @param {Array<String>=} extraCommandArgs
   */
  constructor(args, extraCommandArgs) {
    this.commandArguments = [];
    this.extraCommandArgs = extraCommandArgs;
    this.JAR_PATH = compilerPath;
    this.javaPath = javaPath;

    if (Array.isArray(args)) {
      this.commandArguments.push(...args);
    } else {
      for (const [key, val] of Object.entries(args)) {
        if (Array.isArray(val)) {
          this.commandArguments.push(...val.map((item) => this.formatArgument(key, item)));
        } else {
          this.commandArguments.push(this.formatArgument(key, val));
        }
      }
    }

    /** @type {function(...*)|null} */
   this.logger = null;

    /** @type {Object<string, string>} */
    this.spawnOptions = undefined;
  }

  /** @param {function(number, string, string)=} callback */
  run(callback) {
    if (this.JAR_PATH) {
      this.commandArguments.unshift(
          '-XX:+IgnoreUnrecognizedVMOptions',
          '--sun-misc-unsafe-memory-access=allow',
          '-jar',
          this.JAR_PATH,
      );
      if (this.extraCommandArgs) {
        this.commandArguments.unshift(...this.extraCommandArgs);
      }
    }

    if (this.logger) {
      this.logger(this.getFullCommand() + '\n');
    }
    let compileProcess = spawn(this.javaPath, this.commandArguments, this.spawnOptions);

    let stdOutData = '';
    let stdErrData = '';
    if (callback) {
      if (compileProcess.stdout) {
        compileProcess.stdout.setEncoding('utf8');
        compileProcess.stdout.on('data', (data) => {
          stdOutData += data;
        });
        compileProcess.stdout.on('error', (err) => {
          stdErrData += err.toString();
        });
      }

      if (compileProcess.stderr) {
        compileProcess.stderr.setEncoding('utf8');
        compileProcess.stderr.on('data', (data) => {
          stdErrData += data;
        });
      }

      compileProcess.on('close',  (code) => {
        if (code !== 0) {
          stdErrData = this.prependFullCommand(stdErrData);
        }

        callback(code, stdOutData, stdErrData);
      });

      compileProcess.on('error', (err) => {
        callback(1, stdOutData,
            this.prependFullCommand('Process spawn error. Is java in the path?\n' + err.message));
      });
    }

    return compileProcess;
  }


  /**
   * @return {string}
   */
  getFullCommand() {
    return `${this.javaPath} ${this.commandArguments.join(' ')}`;
  }

  /**
   * @param {string} msg
   * @return {string}
   */
  prependFullCommand(msg) {
    return `${this.getFullCommand()}\n\n${msg}\n\n`;
  }

  /**
   * @param {string} key
   * @param {(string|boolean)=} val
   * @return {string}
   */
  formatArgument(key, val) {
    let normalizedKey = key.replace(/[A-Z]/g, (match) => `_${match.toLowerCase()}`);
    normalizedKey = normalizedKey.replace(/^--/, '');

    if (val === undefined || val === null) {
      return `--${normalizedKey}`;
    }

    return `--${normalizedKey}=${val}`;
  }
};