prototype.js分析 Enumerable

JavaScript

partition() 配列を条件分けする

<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;
	this._each(function(v){
		iterator(v, index++);
	});
}

Array.prototype.collect = function(iterator){
	var iterator = iterator || function(x){return x};
	var rs = [];
	this.each(function(v, k){
		rs.push(iterator(v, k));
	});
	return rs;
}

Array.prototype.partition = function(iterator){
	var trues = [], falses = [];
	this.each(function(v, k){
		(iterator(v, k)? trues : falses).push(v);
	});
	return [trues, falses];
};

var rs = "hoge moge foo bar".split(' ').partition(function(v, k){
	return (v.length > 3);
});
console.log(rs);
</script>