Run results for: Array splice vs array assign

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.6 Safari/605.1.15

Browser: Safari 17

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Object property assign

1.3M/s

Array splice

1.2M/s

View exact numbers

Test name	Executions per second
✓ Object property assign	1,250,126 Ops/sec
Array splice	1,242,518 Ops/sec

Script Preparation code:

var input = [];
for (var i = 0; i < 50000; i++) {
    input.push({
        id: i,
        data: 'something'
    })
}

Tests:

Array splice
const index = input.findIndex(val => val.id === 999); input.splice(index, 1, {id: 999, data: 'somethingElse'});
Object property assign
const index = input.findIndex(val => val.id === 999); input[index] = {id: 999, data: 'somethingElse'}