Simple Gulp dev/build

gulpfile.js

var gulp = require( 'gulp' );
var gulpif = require( 'gulp-if' );
var browserSync = require( 'browser-sync' ).create();
var babel = require( 'gulp-babel' );
var sass = require( 'gulp-sass' );
var sourcemaps = require( 'gulp-sourcemaps' );
var autoprefixer = require( 'gulp-autoprefixer' );
var concat = require( 'gulp-concat' );
var cssnano = require( 'gulp-cssnano' );
var uglify = require( 'gulp-uglify' );
var notify = require( 'gulp-notify' );
var rename = require( 'gulp-rename' );
var changed = require( 'gulp-changed' );
var scsslint = require( 'gulp-scss-lint' );
var cache = require( 'gulp-cached' );
var runSequence = require( 'run-sequence' );

var handleErrors = function () {

	var args = Array.prototype.slice.call( arguments );

	// Send error to notification center with gulp-notify
	notify.onError( {
		title: "Compile Error",
		message: "<%= error %>"
	} ).apply( this, args );

	// Keep gulp from hanging on this task
	this.emit( 'end' );
};

// Set NODE_ENV to development by default
process.env.NODE_ENV = 'development';

// Set NODE_ENV to production when building
gulp.task( 'set-prod-node-env', function () {
	return process.env.NODE_ENV = 'production';
} );

// Build and concatonate justinwhall JS before reload
gulp.task( 'reloadJS', [ 'scripts' ], function () {
	browserSync.reload();
} );

// Open new browser window if --open flag is set
gulp.task( 'browser-sync', function () {

	var option, i = process.argv.indexOf( "--open" );
	if ( i > -1 ) {
		// option = process.argv[i+1];
		option = process.argv[ i ];
	}

	browserSync.init( {
		proxy: 'http://justinwhall.wtf',
		open: ( option ) ? true : true
	} );

} );


gulp.task( 'sass', function () {

	return gulp.src( "./assets/sass/milligram.sass" )
		.pipe( sourcemaps.init() )
		.pipe( sass() )
		.on( 'error', handleErrors )
		.pipe( autoprefixer( { browsers: [ 'last 3 versions' ] } ) )
		.pipe( concat( 'justinwhall.css' ) )
		.pipe( cssnano( {
			'safe': true, // Use safe optimizations.
			keepSpecialComments: 1
		} ) )
		.pipe( sourcemaps.write( './' ) )
		.pipe( gulp.dest( './assets/dist/' ) )
		.pipe( browserSync.stream() );
} );


// justinwhall JavaScript. Included in every page. Concatonated & minified to justinwhall.min.js
gulp.task( 'scripts', function () {
	return gulp.src( [
		// tweenMax
		'./node_modules/gsap/src/uncompressed/TweenMax.js',
		// Navigation
		'./assets/js/justinwhall.js',
		// comment reply
		'./assets/js/comments.js'
	] )

		.pipe( sourcemaps.init() )
		.pipe( concat( 'justinwhall.min.js' ) )
		.pipe( babel( { "presets": [ [ "babel-preset-env", { modules: false }] ] } ) )
		.pipe( gulpif( process.env.NODE_ENV === 'production', uglify() ) )
		.pipe( sourcemaps.write( '.' ) ) // Creates sourcemap for minified JS
		.pipe( gulp.dest( './assets/dist' ) )
} );

// Spin up dev
gulp.task( 'dev', [ 'browser-sync' ], function () {

	// Compile & lint SASS on change
	gulp.watch( "./assets/sass/*.sass", { interval: 500 }, [ 'sass' ] );

	// Reload on PHP/JS changes
	gulp.watch( [ "./**/*.php", "!./node_modules/**" ], { interval: 500 }, browserSync.reload );
	gulp.watch( [ "./assets/js/*.js", "!./node_modules/**/*.js", '!./assets/scripts/dist/**' ], { interval: 500 }, [ 'reloadJS' ] );

} )

// Build for production
gulp.task( 'build', [ 'set-prod-node-env' ], function () {
	runSequence(
		'sass',
		'scripts'
	);
} );