不服跑分。for-loop VS. Array.map VS. Array.every

benchmark.js

function benchmark (times) {
	var index = Math.floor(Math.random()*times);

	function fn (elem, i, array) {
		array[i] = Math.sqrt(array[i]);
		return true;
	}

	var a = [];
	var b = [];
	var c = [];
	var d = [];
	console.time('init');
		for(var i = 0; i < times; ++i) {
			a.push(i);
			b.push(i);
			c.push(i);
			d.push(i);
		} 
	console.timeEnd('init');

	console.time('for');
		for(var i = 0, len = a.length; i < len; ++i) {
			a[i] = Math.sqrt(a[i]);
		}
	console.timeEnd('for');
	console.log('   ' + a[index]);

	console.time('for fn');
		for(var i = 0, len = b.length; i < len; ++i) {
			fn(b[i], i, b);
		}
	console.timeEnd('for fn');
	console.log('   ' + b[index]);

	console.time('map');
		c.map(fn);
	console.timeEnd('map');
	console.log('   ' + c[index]);

	console.time('every');
		d.every(fn);
	console.timeEnd('every');
	console.log('   ' + d[index]);

}

benchmark(0xFFFFF);