Run results for: JavaScript Array Copy

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/25.0 Chrome/121.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 121

Operating system: Android

Device Platform: Mobile

Date tested: 2 years ago

Spread operator

2.1M/s

Array.concat

1.1M/s

Array.slice

211K/s

Slice with begin argument

207K/s

Slice with begin and end argument

174K/s

While loop

100K/s

For loop with declared length

100K/s

For loop

79K/s

View exact numbers

Test name	Executions per second
✓ Spread operator	2,131,906 Ops/sec
Array.concat	1,090,784 Ops/sec
Array.slice	210,663 Ops/sec
Slice with begin argument	206,832 Ops/sec
Slice with begin and end argument	173,716 Ops/sec
While loop	100,050 Ops/sec
For loop with declared length	100,025 Ops/sec
For loop	78,773 Ops/sec

Script Preparation code:

var arrayToCopy = [ "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello", "hello" ];
var shallowCopy = [];

Tests:

Array.concat
shallowCopy = arrayToCopy.concat();
Array.slice
shallowCopy = arrayToCopy.slice();
For loop
for (let i = 0; i < arrayToCopy.length; ++i) { shallowCopy.push(arrayToCopy[i]); }
For loop with declared length
var arrayLength = arrayToCopy.length; for (let i = 0; i < arrayLength; ++i) { shallowCopy.push(arrayToCopy[i]); }
While loop
let i = arrayToCopy.length - 1; while (i--) { shallowCopy.push(arrayToCopy[i]); }
Spread operator
shallowCopy = [...arrayToCopy];
Slice with begin argument
shallowCopy = arrayToCopy.slice(0);
Slice with begin and end argument
shallowCopy = arrayToCopy.slice(0, arrayToCopy.length);