Run results for: Array loop vs foreach vs map populate array with prealloc fixed

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.125 Safari/537.36 Edg/84.0.522.59

Browser: Chrome 84

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Script Preparation code:

var arr = [];
for (var i = 0; i < 1000; i++) {
    arr[i] = i;
}

var arr2 = [];

Tests:

foreach
arr2 = new Array(arr.length); var j = 0; arr.forEach(function (item){ arr2[j] = item; ++j; })
for
arr2 = new Array(arr.length); for (var i = 0, len = arr.length; i < len; i++) { arr2[i] = arr[i]; }
map
arr2 = arr.map(item => item)