GulpUglifyError:Unable to minify JavaScript

Question

I am trying to minify my script files for which i am using gulp task runner And I am trying gulp-uglify plugin

Code:

 gulp.task(\'concat\', function() {         


        

Answer 1

Try using this

var concat = require('gulp-concat');
var uglify = require('gulp-uglify');
var minifyJS = require('gulp-minify');

gulp.task('concat', function() {
    return gulp.src('app/**/*.js')
        .pipe(minifyJS())
        .pipe(concat('bundle.min.js'))
        .pipe(uglify({ mangle: false }))
        .pipe(gulp.dest('./dist/'));
});

Answer 2

I think the top answers here are not explaining how to get the error. The docs have a section on error handling:

gulp-uglify emits an 'error' event if it is unable to minify a specific file

So, just capture the error and do whatever you want with it (such as logging to console) to see the filename, line number, and additional info:

uglify().on('error', console.error)

or in a larger context:

gulp.task('foo', () => {

    return gulp.src([
        'asset/src/js/foo/*.js',
        'asset/src/js/bar/*.js',
    ])
    .pipe(uglify().on('error', console.error))
    .pipe(concat('bundle.js'))
    .pipe(gulp.dest('./'));

});

This gives you a super helpful error!

{ GulpUglifyError: unable to minify JavaScript
    at [stack trace])
  cause:
   { SyntaxError: Continue not inside a loop or switch
       [stack trace]
     message: 'Continue not inside a loop or switch',
     filename: 'ProductForm.js',
     line: 301,
     col: 37,
     pos: 10331 },
  plugin: 'gulp-uglify',
  fileName:
   '/asset/src/js/foo/ProductForm.js',
  showStack: false }