Making Closure Compiler work with Either Grunt or Gulp

Question

I am trying to use Google Closure Compiler on my new project that I plan to write in ES6. I simply try to follow https://www.npmjs.com/package/google-closure-compiler. After I did npm install google-closure-compiler, I tried either the Grunt or the Gulp approach but neither worked for me. I just had a real simple js hello world type of file to test the workflow.

For Grunt my Gruntfile.js:

module.exports = function(grunt) {

  require('google-closure-compiler').grunt(grunt);

  grunt.initConfig({
  'closure-compiler': {
    my_target: {
      files: {
        'dest/output.min.js': ['src/js/**/*.js']
      },
      options: {
        compilation_level: 'SIMPLE',
        language_in: 'ECMASCRIPT6_STRICT',
        language_out: 'ECMASCRIPT5_STRICT',
        create_source_map: 'dest/output.min.js.map',
        output_wrapper: '(function(){\n%output%\n}).call(this)\n//# sourceMappingURL=output.min.js.map'
      }
    }
  }
});

And when I run "grunt" I get:

Warning: Promise is not defined Use --force to continue. Aborted due to warnings.

For Gulp, I also followed the Tutorial, and my gulpfile.js is like this:

var gulp  = require('gulp'),
    gutil = require('gulp-util');

var Promise = require('es6-promise').Promise;
var closureCompiler = require('google-closure-compiler').gulp();

gulp.task('default', function () {
  return gulp.src('./src/js/**/*.js', {base: './'})
      .pipe(closureCompiler({
          compilation_level: 'SIMPLE',
          warning_level: 'VERBOSE',
          language_in: 'ECMASCRIPT6_STRICT',
          language_out: 'ECMASCRIPT5_STRICT',
          output_wrapper: '(function(){\n%output%\n}).call(this)',
          js_output_file: 'output.min.js'
        })).on('error', gutil.log)
      .pipe(gulp.dest('./dist/js'));
});

And when I run gulp intially following the tutorial I ran into the Promise not defined error as well but at least I was able to add that es6-promise line to fix the initial problem but then I still get:

events.js:72
        throw er; // Unhandled 'error' event
              ^
Error: not implemented
    at Readable._read (_stream_readable.js:465:22)
    at Readable.read (_stream_readable.js:341:10)
    at Readable.on (_stream_readable.js:720:14)
    at Readable.pipe (_stream_readable.js:575:10)
    at Transform.CompilationStream._flush (/<my project directory>/node_modules/google-closure-compiler/lib/gulp/index.js:213:17)
    at Transform.<anonymous> (_stream_transform.js:130:12)
    at Transform.g (events.js:180:16)
    at Transform.emit (events.js:117:20)
    at finishMaybe (_stream_writable.js:360:12)
    at endWritable (_stream_writable.js:367:3)

Any help on making either Grunt or Gulp work?

Answer 1

Upgrade your NodeJS version. The plugins assume native Promises support. It works as far back as NodeJS 0.12.