GulpUglifyError:Unable to minify JavaScript

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

Code:

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  •  gulp.task('concat', function() {
        return gulp.src('app/**/*.js')
            // .pipe(concat('script.js'))
            .pipe(uglify())
            .pipe(gulp.dest('./dist/'))
    });
    

    but i am getting error as

    enter image description here

    when i try to run gulp task as gulp concat
    Any help would be appreciated

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  • 4 Solutions collect form web for “GulpUglifyError:Unable to minify JavaScript”

    Have you used ES6 format in your script file?
    If so try ES5 now because when you do gulp-uglify it doesnt understand ES6 format as of now
    and after that try your code

     gulp.task('concat', function() {
        return gulp.src('app/**/*.js')
            .pipe(concat('script.js'))
            .pipe(uglify())
            .pipe(gulp.dest('./dist/'))
    });
    

    and run the task gulp concat it will work

    To see the error in console:

    var gutil = require('gulp-util');
    
    gulp.task('concat', function() {
    return gulp.src('app/**/*.js')
        // .pipe(concat('script.js'))
        .pipe(uglify())
        .on('error', function (err) { gutil.log(gutil.colors.red('[Error]'), err.toString()); })
        .pipe(gulp.dest('./dist/'))
    });
    

    To find the exact file with line no of error register and run this task:

    var pump = require('pump');
    
    gulp.task('uglify-error-debugging', function (cb) {
      pump([
        gulp.src('app/**/*.js),
        uglify(),
        gulp.dest('./dist/')
      ], cb);
    });
    

    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/'));
    });
    

    The main error to Unable to minifies JavaScript is the path not found. You can use the task usemin For this you need:

    $ sudo npm install gulp-usemin --save-dev
    $ sudo npm install gulp-livereload--save-dev
    $ sudo npm install gulp-util--save-dev
    

    and requires :

    var usemin = require('gulp-usemin');
    var livereload = require('gulp-livereload');
    var gutil = require('gulp-util'); //gutil for error display
    
    gulp.task('usemin',['jshint'], function(){
        return gulp.src('./app/index.html')
        .pipe(usemin({
            css: [minifycss(),rev()],
            scripts: [uglify().on('error', function(err) {gutil.log(gutil.colors.red('[Error]'), err.toString());this.emit('end');}),rev()]
        })) 
        .pipe(gulp.dest('dist'))
        .pipe(livereload());
    });
    
    Change the js: [uglify(), rev()] to scripts: [uglify(), rev()]