Run results for: Map vs For Loop

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Firefox/52.0

Browser: Firefox 52

Operating system: Mac OS X 10.12

Device Platform: Other

Date tested: 7 years ago

Script Preparation code:

var a = new Array(1e6);
for (var i = 0; i < 1e6; i++) {
  a[i] = Math.random();
}

Tests:

Map
var b = a.map(n => n * 2);
For Loop
var b = []; for (var i = 0; i < a.length; i++) { b[i] = a[i] * 2; }
For Loop -- Cached array length
var b = []; var len = a.length; for (var i = 0; i < len; i++) { b[i] = a[i] * 2; }