src/talks/wasm/examples/4-primes-sieve/script.js


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import Primes from "./primes.mjs";

var primes = await Primes();

var input = document.getElementById("input");
var wasm_button = document.getElementById("wasmButton");
var js_button = document.getElementById("jsButton");
var resultText = document.getElementById("resultText");

var count_wasm = (n) => primes._count(n);

var count_js = (n) => {
	if (n < 2)
		return 0;

	var notprime = new Uint8Array(n+2);

	var count = 0;
	for (var i = 2; i < n; i++) {
		count += 1 - notprime[i];
		for (var j = 2*i; j < n; j += i)
			notprime[j] = 1;
	}

	return count;
}

var timerun = (count, tag) => {
	var n = Number(input.value);
	var msg = "Counting primes less than " + n + " with " + tag;
	console.time(msg);
	var c = count(n);
	console.timeEnd(msg);
	resultText.innerText = "There are " + c + " primes less than " + n;
}

wasm_button.addEventListener("click", () => timerun(count_wasm, "WASM"));
js_button.addEventListener("click", () => timerun(count_js, "JS"));