Run results for: Reduce: concat vs push

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36

Browser: Chrome 149

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one month ago

Reduce + concat

245K/s

Reduce + push

21K/s

View exact numbers

Test name	Executions per second
✓ Reduce + concat	245,319 Ops/sec
Reduce + push	21,105 Ops/sec

Script Preparation code:

a = new Array(1000).fill(0).map(() => ({
    value: Math.random(),
    keep: Math.random() > 0.5
}));

Tests:

Reduce + concat
a.reduce((acc, { value, keep }) => { if (keep) { acc.push(value); } return acc; }, []);
Reduce + push
a.reduce((acc, { value, keep }) => (keep ? acc.concat([value]) : acc), []);