async-queue.js
function (err) {
		if (this.jobs.length) {
			var job = this.jobs.shift();
			try {
				job(err, this);
			} catch (e) {
				this.next(e);
			}
		} else {
			this.running = false;
		}
	}
function (err) {
		if (this.jobs.length) {
			var job = this.jobs.shift();
			try {
				job(err, this);
			} catch (e) {
				this.next(e);
			}
		} else {
			this.running = false;
		}
	}
function ( err ) { if ( this . jobs . length ) { var job = this . jobs . shift ( ) ; try { job ( err , this ) ; } catch ( e ) { this . next ( e ) ; } } else { this . running = false ; } }
Run the next job in queue

@private
@param  {Object} err
Run the next job in queue