Web Workersを利用した素数一覧表示テスト

prime.js

var worker = createWorker(workerScript);
console.time("prime");
worker.postMessage(1000000);
worker.addEventListener("message", function (event) {
	console.timeEnd("prime");
	document.querySelector("body").innerHTML = event.data.join(", ");
});

function createWorker(script) {
	var re = /^function\s*\w*\s*\([\w\s,]*\)\s*{([\w\W]*?)}$/,
		body = script.toString().trim().match(re)[1],
		blob = new Blob([body], {type: "text/javascript"}),
		url = URL.createObjectURL(blob);
	return new Worker(url);
}

function workerScript() {
	
	addEventListener("message", function (event) {
		postMessage(prime(event.data));
	});
	
	function prime(limit) {
		var primes = [];
		if (limit < 2) return primes;
		primes.push(2);
		if (limit <= 2) return primes;
		for (var i=3; i <= limit; i++) {
			for (var j=0; j < primes.length; j++) {
				if (i % primes[j] === 0) break;
				if (j+1 >= primes.length) primes.push(i);
			}
		}
		return primes;
	}
}