Benchmark: JavaScript Array Copy 3

Script Preparation code:

var arrayToCopy = new Array(1000).fill(5);
var shallowCopy = [];

Tests:

Array.concat
shallowCopy = arrayToCopy.concat();
Array.slice
shallowCopy = arrayToCopy.slice();
For loop no push
var arrayLength = arrayToCopy.length; shallowCopy.length = arrayLength; for (let i = 0; i < arrayLength; ++i) { shallowCopy[i] = arrayToCopy[i]; }
For loop no push, prefill
var arrayLength = arrayToCopy.length; for (let i = 0; i < arrayLength; ++i) { shallowCopy[i] = arrayToCopy[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.concat
Array.slice
For loop no push
For loop no push, prefill

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser/OS: Chrome 140 on Mac OS X 10.15.7

View result in a separate tab

Array.concat

8.0M/s

Array.slice

7.9M/s

For loop no push

617K/s

For loop no push, prefill

612K/s

View exact numbers

Test name	Executions per second
✓ Array.concat	7,962,596 Ops/sec
Array.slice	7,868,622 Ops/sec
For loop no push	617,042 Ops/sec
For loop no push, prefill	612,389 Ops/sec

JavaScript Array Copy 3 (version: 1)

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

Comparing performance of: `Array.concat vs Array.slice vs For loop no push vs For loop no push, prefill`

Created: 10 months ago by: Guest

Go to the latest result

Array.concat

Array.slice

For loop no push

For loop no push, prefill

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

JavaScript Array Copy 3 (version: 1)

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

Comparing performance of: Array.concat vs Array.slice vs For loop no push vs For loop no push, prefill

Created: 10 months ago by: Guest

Go to the latest result

Array.concat

Array.slice

For loop no push

For loop no push, prefill

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `Array.concat vs Array.slice vs For loop no push vs For loop no push, prefill`