Run results for: Array filter vs. for loop - with for in 2

Run details:

User agent: Mozilla/5.0 (Linux; Android 8.0.0; Build/OPR6.170623.013) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.111 Mobile Safari/537.36

Browser: Chrome Mobile 63

Operating system: Android 8.0.0

Device Platform: Other

Date tested: 2025 years ago

Test name	Executions per second
Filter	366568.2 Ops/sec
For	43751.9 Ops/sec
For 2	47351.9 Ops/sec
For in	61248.9 Ops/sec

Script Preparation code:

var arr = [1,2,3,4,null,5,6,"7",8,{a:2},0], farr=[], i,len;

Tests:

Filter
farr = arr.filter(function(item) { return (item>4); });
For
for (i=0,len=arr.length;i<len;i++) { if (arr[i]<5) continue; farr.push(arr[i]); }
For 2
for (i=0,len=arr.length;i<len;i++) { if (arr[i]>4) farr.push(arr[i]); }
For in
for (i in arr) { if (arr[i]>4) farr.push(arr[i]); }

Run results for: Array filter vs. for loop - with for in 2

This version declares i once before

Filter

For

For 2

For in