Human readable bytes size in JavaScript

humanbytes.js

function formatSize(bytes, si) {
	var unit = si ? 1000 : 1024;
	if (bytes < unit) return (bytes % 1 === 0 ? bytes : bytes.toFixed(2)) + "B";
	var exp =  parseInt(Math.log(bytes) / Math.log(unit));
	console.log(exp)
	var pre = (si ? "kMGTPE" : "KMGTPE")[exp-1] + (si ? "" : "i")+'B';
	var n = bytes / Math.pow(unit, exp);
	return (n % 1 === 0 ? n : n.toFixed(2))+pre;
}