gulpfile.js
function clean(done) {
	var del = require('del');
	del(cfg.destination).then(function () {
		if (typeof done === 'function') done();
		else process.exit();
	});
}
function clean(done) {
	var del = require('del');
	del(cfg.destination).then(function () {
		if (typeof done === 'function') done();
		else process.exit();
	});
}
function clean ( done ) { var del = require ( 'del' ) ; del ( cfg . destination ) . then ( function ( ) { if ( typeof done === 'function' ) done ( ) ; else process . exit ( ) ; } ) ; }
cleanup after itself
cleanup after itself