Benchmark: [Array 10] flatMap vs reduce (concat) vs reduce (push)

Script Preparation code:

var arr = Array(10).fill(1)

Tests:

Reduce concat
arr.reduce((acc, x, index) => acc.concat(x, index % 2 ? x : []), [])
FlatMap
arr.flatMap((x, index) => [x, index % 2 && x]).filter(Boolean)
Reduce push
arr.reduce((acc, x, index) => { acc.push(x); if(index % 2) { acc.push(x) } return acc; }, [])

Rendered benchmark preparation results:

Previous results

ⓘ Get performance results from real users on your website with Request Metrics.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36

Browser/OS: Chrome 98 on Windows

[Array 10] flatMap vs reduce (concat) vs reduce (push) (version: 0)