bench_prototype_chain.js
No OneTemporary
Actions

Size

1 KB

Referenced Files

None

Subscribers

None

bench_prototype_chain.js
View Options

	function nowMs() {
	return Date.now();
	}

	function makeChain(depth) {
	function C() {}
	const root = { marker: 1 };
	C.prototype = root;

	let obj = Object.create(root);
	for (let i = 0; i < depth; i++) obj = Object.create(obj);
	return { C, obj, root };
	}

	function bench(label, fn, iters) {
	const t0 = nowMs();
	const result = fn(iters);
	const dt = nowMs() - t0;
	const opsPerMs = dt > 0 ? (iters / dt).toFixed(2) : 'inf';
	console.log(label + ': ' + dt + 'ms (' + opsPerMs + ' ops/ms) result=' + result);
	}

	function runDepth(depth) {
	const iters = 2_000_000;
	const { C, obj, root } = makeChain(depth);

	console.log('\n=== depth=' + depth + ' ===');
	console.log('sanity instanceof=' + (obj instanceof C));
	console.log('sanity isPrototypeOf=' + root.isPrototypeOf(obj));
	console.log('sanity marker=' + obj.marker);

	bench(
	'instanceof',
	n => {
	let c = 0;
	for (let i = 0; i < n; i++) if (obj instanceof C) c++;
	return c;
	},
	iters
	);

	bench(
	'isPrototypeOf',
	n => {
	let c = 0;
	for (let i = 0; i < n; i++) if (root.isPrototypeOf(obj)) c++;
	return c;
	},
	iters
	);

	bench(
	'prop_lookup',
	n => {
	let c = 0;
	for (let i = 0; i < n; i++) c += obj.marker;
	return c;
	},
	iters
	);
	}

	console.log('prototype-chain benchmark');
	runDepth(8);
	runDepth(24);
	runDepth(40);