Run results for: JavaScript Array Copy 2

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 130

Operating system: Android

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
Array.concat	4649053.5 Ops/sec
Array.slice	4734883.0 Ops/sec
For loop	141941.6 Ops/sec
For loop with declared length	216816.4 Ops/sec
While loop	227307.5 Ops/sec
Spread operator	4433834.5 Ops/sec
Slice with begin argument	4698655.5 Ops/sec
Slice with begin and end argument	2841522.0 Ops/sec
Array.from	3519931.5 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);
Array.from
shallowCopy = Array.from(arrayToCopy);

Run results for: JavaScript Array Copy 2

Testing the results for the fastest approach of shallow copying an array in JavaScript (concat, slice, for loop, and while loop).

Array.concat

Array.slice

For loop

For loop with declared length

While loop

Spread operator

Slice with begin argument

Slice with begin and end argument

Array.from