Run results for: JavaScript spread operator vs Slice/Splice performance - 2

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_4_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4.1 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 17

Operating system: iOS 17.4.1

Device Platform: Mobile

Date tested: 2 years ago

Array clone with spread operator

23.1M/s

Array clone with slice

16.1M/s

Array addition with spread operator

12.5M/s

Array addition with slice and push

8.5M/s

View exact numbers

Test name	Executions per second
✓ Array clone with spread operator	23,071,068 Ops/sec
Array clone with slice	16,068,317 Ops/sec
Array addition with spread operator	12,467,183 Ops/sec
Array addition with slice and push	8,467,081 Ops/sec

Script Preparation code:

const ITERATIONS = 500000;
var index = ITERATIONS/2;
var n = Math.random();

var list = [];
for (let i = 0; i < length; i += 1) {
  list.push(Math.random());
}

Tests:

Array clone with spread operator
const clone = [...list];
Array clone with slice
const clone = list.slice();
Array addition with spread operator
const clone = [...list, n];
Array addition with slice and push
const clone = list.slice(); clone.push(n);