Run results for: JavaScript Array Copy Test 2

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36

Browser: Chrome 104

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Slice with begin argument

4.1M/s

Array.slice

3.9M/s

Spread operator

3.9M/s

Array.concat

3.8M/s

Slice with begin and end argument

2.5M/s

While loop

184K/s

For loop with declared length

165K/s

Object Assign

125K/s

For loop

119K/s

View exact numbers

Test name	Executions per second
✓ Slice with begin argument	4,145,791 Ops/sec
Array.slice	3,943,376 Ops/sec
Spread operator	3,918,886 Ops/sec
Array.concat	3,767,114 Ops/sec
Slice with begin and end argument	2,504,866 Ops/sec
While loop	183,800 Ops/sec
For loop with declared length	164,761 Ops/sec
Object Assign	124,948 Ops/sec
For loop	118,533 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);
Object Assign
shallowCopy = Object.assign([], arrayToCopy);