Benchmark: Array reduce using: push VS splice VS spread at beginning VS spread at end

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], []);

Rendered benchmark preparation results:

Previous results

Test case name	Result
push()
splice (reverse order)
spread at beginning (reverse order)
spread at end

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36

Browser/OS: Chrome 142 on Mac OS X 10.15.7

push()

10K/s

splice (reverse order)

477/s

spread at end

10/s

spread at beginning (reverse order)

2/s

View exact numbers

Test name	Executions per second
✓ push()	9,572 Ops/sec
splice (reverse order)	477 Ops/sec
spread at end	10 Ops/sec
spread at beginning (reverse order)	2 Ops/sec

Array reduce using: push VS splice VS spread at beginning VS spread at end (version: 1)