for loop vs forEach

Compares a classic indexed for loop against Array.prototype.forEach for summing an array.

Shazzer Elite

Created Jul 3, 2026

Updated Jul 4, 2026

Unable to render tweet button

Detecting browser...

CategoryJavaScript Syntax

VisibilityPublic

TypePERF

CharsetUTF-8

Code used before fuzz:

var iterations = 20000;0x0D
var arr=Array.from({length:1000},function(_,i){return i});

Snippet A:

var t=0;for(var i=0;i<arr.length;i++){t+=arr[i]}

Snippet B:

var t=0;arr.forEach(function(n){t+=n});

Sample payloads

var t=0;for(var i=0;i<arr.length;i++){t+=arr[i]}

var t=0;arr.forEach(function(n){t+=n});

Snippet A

var t=0;for(var i=0;i<arr.length;i++){t+=arr[i]}

Snippet B

var t=0;arr.forEach(function(n){t+=n});

Browser	Snippet A	Snippet B	Winner
1stChrome150.0.7871.47	13.70 ms	39.30 ms	Snippet A2.87× faster

Median of 5 trials × 20,000 iterations per snippet.