Run results for: Array.prototype.concat vs Spread speedtest

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 12_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/74.0.3729.121 Mobile/15E148 Safari/605.1

Browser: Chrome Mobile iOS 74

Operating system: iOS 12.2

Device Platform: Mobile

Date tested: 5 years ago

Test name	Executions per second
Array.prototype.concat	1.1 Ops/sec
Spread operator	0.3 Ops/sec

Script Preparation code:

function generateRandomNumbers(m) {
  const array = new Uint32Array(m);
  window.crypto.getRandomValues(array);
  return Array.prototype.map.call(array, val => val);
}

function generateRandomArrays(n, m) {
  const array = [];
  for (let i = 0; i < n; i++) {
	array.push(generateRandomNumbers(m))
  }
  return array;
}


var array = generateRandomArrays(1e4, 1e1);

Tests:

Array.prototype.concat
const b = array.reduce((accumulator, value) => accumulator.concat(value));
Spread operator
const c = array.reduce((accumulator, value) => [...accumulator, ...value]);

Run results for: Array.prototype.concat vs Spread speedtest

Array.prototype.concat

Spread operator