for loop vs forEach

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

Shazzer Master

Created Jul 3, 2026

Updated Jul 4, 2026

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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
1stFirefox153.0	9.00 ms	76.00 ms	Snippet A8.44× faster
2ndSafari26.5.2	9.00 ms	32.00 ms	Snippet A3.56× faster
3rdMicrosoft Edge151.0.4129.59	79.40 ms	157.30 ms	Snippet A1.98× faster
4thChrome