Run results for: MapFIlter vs. Reduce

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.122 Safari/537.36

Browser: Chrome 81

Operating system: Mac OS X 10.15.2

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
MapFilter	15.5 Ops/sec
Reduce	14.5 Ops/sec

Script Preparation code:

window.largeArr = [];
for(i=0; i<1000000; i++){
  window.largeArr.push([i.toString(), i])
  if (Math.random() < 0.1) window.largeArr.push([undefined, i])
}

Tests:

MapFilter
window.largeArr.map(el => el[0]).filter(Boolean)
Reduce
window.largeArr.reduce((all, el) => { if (el[0]) { all.push(el[0]); } return all; }, [])

Run results for: MapFIlter vs. Reduce

MapFilter

Reduce