Benchmark: flatMap vs reduce array generation

Tests:

flatMap
const workFromHour = 13; const workToHour = 23; const timeOptionsList = Array.from({ length: workToHour - workFromHour, }).flatMap((_, index) => { const calculatedIntervalHour = +workFromHour + index; return [{label: `${calculatedIntervalHour}:00`, value: `${calculatedIntervalHour}:00`, }, { label: `${calculatedIntervalHour}:30`, value: `${calculatedIntervalHour}:30`, }, ]; }, []); console.log(timeOptionsList);
reduce
const workFromHour = 13; const workToHour = 23; const timeOptionsList = Array.from({ length: workToHour - workFromHour, }).reduce((acc, _, index) => { const calculatedIntervalHour = workFromHour + index; return [ ...acc, { label: `${calculatedIntervalHour}:00`, value: `${calculatedIntervalHour}:00`, }, { label: `${calculatedIntervalHour}:30`, value: `${calculatedIntervalHour}:30`, }, ]; }, []); console.log(timeOptionsList);

Rendered benchmark preparation results:

Previous results

Test case name	Result
flatMap
reduce

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Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.182 Safari/537.36

Browser/OS: Chrome 88 on Linux

Test name	Executions per second
flatMap	37523.0 Ops/sec
reduce	46019.7 Ops/sec

flatMap vs reduce array generation (version: 0)