Run results for: Spread vs Slice

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36

Browser: Chrome 66

Operating system: Mac OS X 10.13.4

Device Platform: Other

Date tested: 6 years ago

Test name	Executions per second
Array.slice	1653501.0 Ops/sec
Babel spread	1071861.0 Ops/sec

HTML Preparation code:


<div id='x'></div>

Script Preparation code:

var el = document.getElementById('x');
function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

Tests:

Array.slice
var list = Array.prototype.slice.apply(el.classList);
Babel spread
var list = [].concat(_toConsumableArray(el.classList));

Run results for: Spread vs Slice

Cast a classList to an array with Array.prototype.slice.apply() or the babel transpile of [...classList]

Array.slice

Babel spread