Grunt Uglify无法通过ES6

Question

I'm using grunt to uglify three JavaScript files:

1. functions.js
2. formdata.min.js
3. page-contact.js

I'm getting this error:

Warning: Uglification failed.
Name expected.
Line 38 in src/js/functions.js
 Use --force to continue.

Line 38 of functions.js :

for (var [id, value] of formData.entries()) {

Is this failing on the for...of or the formData?

The Gruntfile.js :

module.exports = function(grunt) {
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    watch: {
      uglify: {
        files: [ 'src/js/*' ],
        tasks: 'uglify'
      }
    },
    uglify: {
      my_target: {
        files: {
          'public/js/<%= pkg.name %>.min.js': ['src/js/*.js']
        }
      }
    }
  });

  grunt.loadNpmTasks('grunt-contrib-watch');
  grunt.loadNpmTasks('grunt-contrib-uglify');

};

Answer 1

Solved this by switching to the harmony branch of grunt-contrib-uglify . The master branch doesn't support ES6 at this time.

In my packages.json I swapped out the original line for this and ran npm install :

"grunt-contrib-uglify": "git://github.com/gruntjs/grunt-contrib-uglify.git#harmony"