object.keys vs for-in

Benchmark created on

Setup

const ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

function randomString(length) {
  const out = [];
  for (let i = 0; i < length; i++) {
    const randomChar = ALPHABET[Math.floor(Math.random() * ALPHABET.length)];
    out.push(randomChar);
  }
  return out.join("");
}

function randomObject(size) {
  const out = {};
  for (let i = 0; i < size; i++) {
  	out[randomString(10)] = Math.random();
  }
  return out;
}

const data = randomObject(10_000);

Test runner

Ready to run.

Testing in
TestOps/sec
object.keys
function current(data) {
  return Object.keys(data).length === 0;
}

current(data);
ready
for-in
function suggested(data) {
  for (const key in data) {
    if (Object.hasOwn(data, key)) {
      return false;
    }
  }
  return true;
}

suggested(data);
ready

Revisions

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