Run results for: flatMap vs reduce using push spread vs map flat - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.110 Safari/537.36

Browser: Chrome 96

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
reduce with spread	3009.6 Ops/sec
flatMap	269.8 Ops/sec
map flat	274.1 Ops/sec
reduce with concat	18.9 Ops/sec

Website performance monitoring

Script Preparation code:

var arr = Array(10_000).fill({arr: [0,1]})

Tests:

reduce with spread
arr.reduce((acc, x) => {acc.push(...x.arr); return acc}, [])
flatMap
arr.flatMap(x => x.arr)
map flat
arr.map(x => x.arr).flat()
reduce with concat
arr.reduce((acc, x) => acc.concat(x.arr), [])