Run details:
Mozilla/5.0 (iPhone; CPU iPhone OS 15_1_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.1 Mobile/15E148 Safari/604.1
Mobile Safari 15
iOS 15.1.1
Mobile
3 years ago
Test name Executions per second
reduce with concat 6.8 Ops/sec
flatMap 12222.9 Ops/sec
Script Preparation code:
AخA
 
var arr = Array(10_000).fill(0)
Tests:
  • reduce with concat

     
    arr.reduce((acc, x) => [...acc, x, x], [])
  • flatMap

     
    arr.flatMap(x => [x, x])