SOURCE

var before = function(fn,beforefn){
			return function(){
				beforefn.apply(this,arguments)
				return fn.apply(this,arguments)
			}
		}

		var a = before(
			function(){
				console.log(3)
			},
			function(){
				console.log(2)
			}
			)

		a = before(a,function(){console.log(1)});
		a();