Benchmark: Map vs preallocation vs slice vs spread

Script Preparation code:

var array = Array.from(new Array(1000000), (e, i) => Math.random());

Tests:

Map
var array2 = array.map((e, i) => e);
from
var array2 = Array.from(new Array(1000000), (e, i) => array[i]);
splice
var array2 = array.slice();
spread
var array2 = [...array];
loop
var array2 = new Array(1000000).fill(0), n=array2.length; for (let i = 0; i < n; i++) array2[i] = i;

Rendered benchmark preparation results:

Previous results

ⓘ Get performance results from real users on your website with Request Metrics.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:103.0) Gecko/20100101 Firefox/103.0

Browser/OS: Firefox 103 on Windows

Map vs preallocation vs slice vs spread (version: 0)