Run results for: reduce() + concat() vs filter() then map()

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.54 Safari/537.36 Edg/101.0.1210.39

Browser: Chrome 101

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
reduce() + concat()	9875014.0 Ops/sec
filter() then map()	1473670.0 Ops/sec

Tests:

reduce() + concat()
const arr = [{a: 1}, {a: 2}, {a: 1}, {a: 1}, {a: 2}, {a: 1}, {a: 1}, {a: 2}, {a: 1}, {a: 1}, {a: 2}, {a: 1}, {a: 1}, {a: 2}, {a: 1}]; const filterMap = arr.filter(x => x.a !== 1).map(x => x.a)
filter() then map()
const arr = [{a: 1}, {a: 2}, {a: 1}, {a: 1}, {a: 2}, {a: 1}, {a: 1}, {a: 2}, {a: 1}, {a: 1}, {a: 2}, {a: 1}, {a: 1}, {a: 2}, {a: 1}]; const reduceConcat = arr.reduce((acc, val) => val.a === 1 ? acc : acc.concat([val.a]), []);