Run results for: Reduce: concat vs push

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36 Edg/142.0.0.0

Browser: Chrome 142

Operating system: Windows

Device Platform: Desktop

Date tested: 9 months ago

Reduce + concat

154K/s

Reduce + push

7K/s

View exact numbers

Test name	Executions per second
✓ Reduce + concat	154,008 Ops/sec
Reduce + push	7,194 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), []);