prototype.js分析 Enumerable

JavaScript

detect() / find() 要素を見つける

<script>
Array.prototype._each = function(iterator){
	for(var i=0, l=this.length; i<l; i++){
		iterator(this[i]);
	}
};

Array.prototype.each = function(iterator){
	var index = 0;
	try{
		this._each(function(v){
			iterator(v, index++);
		});
	} catch(e){
		if(e != $break) throw e;
	}
};

Array.prototype.detect = function(iterator){
	var rs;
	this.each(function(v, k){
		if(iterator(v, k)){
			rs = v;
			throw $break;
		}
	});
	return rs;
};

var $break = {};

var kekka = "foo,bar,hoge".split(',').detect(function(v, k){
	if(v.length >= 4) return v;
});
console.log(kekka);
</script>