Simple benchmark showing performance regression in recent versions of Node.js

sum-of-squares.js

const size = 32000000;
const rand = () => Math.random() * 100;

console.log('Generating test data...');

let data = new Array(size);

for (let i = 0; i < size; i++) {
	data[i] = rand();
}

const run = () => {
	console.log('Starting tests...');

	const benchmarks = [
		runMapReduce,
		runForEach,
		runForLoop,
		runForLoopNoLength
	];

	benchmarks.forEach((func) => {
		const results = [ ];

		for (let i = 0; i < 3; i++) {
			results[i] = func();
		}

		console.log(
			func.name.padEnd(20, ' ') +
			formatDuration(results[0]) +
			formatDuration(results[1]) +
			formatDuration(results[2])
		);
	});
};

const runMapReduce = () => runWithTimer(() => {
	const result = data
		.map((x) => x ** 2)
		.reduce((memo, x) => memo + x, 0);
});

const runForEach = () => runWithTimer(() => {
	let result = 0;

	data.forEach((x) => {
		result += x ** 2;
	});
});

const runForLoop = () => runWithTimer(() => {
	let result = 0;

	for (let i = 0; i < data.length; i++) {
		result += data[i] ** 2;
	}
});

const runForLoopNoLength = () => runWithTimer(() => {
	let result = 0;

	for (let i = 0; i < size; i++) {
		result += data[i] ** 2;
	}
});

const runWithTimer = (func) => {
	const start = process.hrtime();

	func();

	const end = process.hrtime();

	return msDiff(start, end);
};

const formatDuration = (ms) => {
	return `${ms.toPrecision(6)}ms`.padEnd(12, ' ');
};

const msDiff = (start, end) => {
	const secondDiff = end[0] - start[0];
	const nanosecondDiff = end[1] - start[1];

	return (secondDiff + nanosecondDiff / 1e9) * 1000;
};



run();