Run results for: flatMap() vs filter().map()

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 14_8_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.1.2 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 14

Operating system: iOS 14.8.1

Device Platform: Mobile

Date tested: 3 years ago

Test name	Executions per second
filter().map()	2424.0 Ops/sec
flatMap()	1508.8 Ops/sec

Script Preparation code:

var arr = [];
var i = 0;

while (i <= 1E5) arr[i] = i++;

​x
 
var arr = [];var i = 0;​while (i <= 1E5) arr[i] = i++;

Tests:

filter().map()
arr.filter(x => x % 3).map(x => x/100)
arr.filter(x => x % 3).map(x => x/100)
flatMap()
arr.flatMap(x => x % 3 ? x/100 : [])
arr.flatMap(x => x % 3 ? x/100 : [])

Run results for: flatMap() vs filter().map()

flatMap vs filter map

filter().map()

flatMap()