Run results for: empty an array in JavaScript - [] vs setting length

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0

Browser: Firefox 137

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

New empty array

70K/s

Set length to zero

52K/s

View exact numbers

Test name	Executions per second
✓ New empty array	70,404 Ops/sec
Set length to zero	52,476 Ops/sec

Tests:

Set length to zero
var size = 10000; var arr2 = []; for (var i = 0; i < size; i++){ arr2.push(i); } arr2.length = 0;
New empty array
var size = 10000; var arr3 = []; for (var i = 0; i < size; i++){ arr3.push(i); } arr3 = [];