Run results for: Array splice is slow

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser: Chrome 126

Operating system: Windows

Device Platform: Desktop

Date tested: 4 months ago

Test name	Executions per second
With Array.splice	19900116.0 Ops/sec
Tweaked version	50846740.0 Ops/sec

Tests:

With Array.splice
function arrayInsert(array, index, value) { array.splice(index, 0, value); } const months = ['Jan', 'March', 'April', 'June']; arrayInsert(months, 1, 'Feb');
Tweaked version
function arrayInsert(array, index, value) { let end = array.length; while (end > index) { const previousEnd = end - 1; array[end] = array[previousEnd]; end = previousEnd; } array[index] = value; } const months = ['Jan', 'March', 'April', 'June']; arrayInsert(months, 1, 'Feb');