Run results for: Flat map + filter vs. Reduce

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36 Edg/148.0.0.0

Browser: Chrome 148

Operating system: Windows

Device Platform: Desktop

Date tested: 2 months ago

reduce

14K/s

flat map + filter

5K/s

View exact numbers

Test name	Executions per second
✓ reduce	14,178 Ops/sec
flat map + filter	4,605 Ops/sec

Script Preparation code:

var arr = Array.from({length:10000}, (v, i) => ({name: i, assigned: Math.random() < 0.5}));

Tests:

flat map + filter
arr.flatMap((o) => (o.assigned ? [o.name] : [])).filter(Boolean);
reduce
arr.reduce((a, o) => (o.assigned && a.push(o.name), a), [])