Run results for: Array reduce using: push VS splice VS spread at beginning VS spread at end

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:146.0) Gecko/20100101 Firefox/146.0

Browser: Firefox 146

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 8 months ago

push()

15K/s

splice (reverse order)

245/s

spread at beginning (reverse order)

6/s

spread at end

6/s

View exact numbers

Test name	Executions per second
✓ push()	15,075 Ops/sec
splice (reverse order)	245 Ops/sec
spread at beginning (reverse order)	6 Ops/sec
spread at end	6 Ops/sec

Script Preparation code:

const items = Array.from({ length: 10000 }).map((_, i) => i + 1);

Tests:

push()
const itemsFilled = items.reduce((list, item) => { list.push(`item #${i}`); return list; }, []);
splice (reverse order)
const itemsFilled = items.reduce((list, item) => { list.splice(0, 0, `item #${i}`); return list; }, []);
spread at beginning (reverse order)
const itemsFilled = items.reduce((list, item) => [...list, `item #${i}`], []);
spread at end
const itemsFilled = items.reduce((list, item) => [`item #${i}`, ...list], []);