gulpfile.js

/**
 * Created by aleksejs.gordejevs on 10/20/2016.
 */
var gulp = require('gulp');
var pathToLib = './lib/';
var size = require('gulp-filesize');
var sourcemaps = require('gulp-sourcemaps');
var uglify = require('gulp-uglify');
var rename = require('gulp-rename');
var concat = require('gulp-concat');
var rimraf = require('gulp-rimraf');
var jshint = require('gulp-jshint');
var gulpFilter = require('gulp-filter');

gulp.task('clean-js', function() {
  var filter = gulpFilter(['**/*.min.js','**/*.js.map']);
  return gulp.src(pathToLib + '**', {read: false})
        .pipe(filter)
        .pipe(rimraf({force: true}));
});

gulp.task('uglify-js', gulp.series('clean-js', function() {
  var filter = gulpFilter(['*/*.js', '!*.min.js']);
  return gulp.src(pathToLib + '*')
        .pipe(filter)
        //.pipe(sourcemaps.init({loadMaps: true}))
        .pipe(uglify({mangle: false}))
        .pipe(rename({suffix: '.min'}))
        .pipe(size())
        //.pipe(sourcemaps.write('./'))
        .pipe(gulp.dest(pathToLib));
  })
);

gulp.task('jshint', function() {
  var filter = gulpFilter(['/*.js', '!*.min.js']);
  return gulp.src(pathToLib)
        .pipe(filter)
        .pipe(jshint())
        .pipe(size())
        .pipe(jshint.reporter('default'));
});

gulp.task('default', gulp.series('jshint', 'uglify-js'));