gulpfile.js

/**
* Install Gulp in Global
* $ npm install gulp -g
*
* Install Gulp in local
* $ npm install gulp --save-dev
*
* Install dependecies Gulp
* $ npm install gulp-concat gulp-uglify gulp-sourcemaps --save-dev
* 
* Run:
*  Run task default - Only concat
*    $ gulp
*
*  Run task script - Only concat
*    $ gulp scripts
*
*  Run task default - Concat and mimify for production
*    $ gulp --prod
* 
*  Run task script - Concat and mimify for production
*    $ gulp scripts --prod
*/

var src = {
        scripts: './src/scripts/**/*.js'
    },
    dist = {
        scripts: './dist/'
    },
    concat = {
        scripts: 'namefile.js'
    };

var gulp = require('gulp'),
    args = require('yargs').argv,
    $ = require('gulp-load-plugins')({ lazy: true });

gulp.task('scripts', ['clean-scripts'], function () {
    return gulp
      .src(src.scripts)
      .pipe($.if(args.prod, $.sourcemaps.init()))
      .pipe($.concat(concat.scripts))
      .pipe($.if(args.prod, $.uglify()))
      .pipe($.if(args.prod, $.sourcemaps.write()))
      .pipe(gulp.dest(dist.scripts));
});

gulp.task('clean-scripts', function () {
    return clean(gulp.dest(src.scripts));
});

gulp.task('default', ['clean-scripts', 'scripts']);