Standard JavaScript practice for iterating through an entire array?

Question

Suppose I want to loop through an entire array to access each element. Is it standard practice amongst JavaScript developers to use a for loop, for...in loop, or for...of loop?

For example:

var myArray = ["apples", "oranges", "pears"];

For loop

for (var index = 0; index < myArray.length; index++)
    console.log(myArray[index]);

For...in loop

for (var index in myArray)
    console.log(myArray[index]);

For...of loop

for (var element of myArray)
    console.log(element);

Also, you can do `var i = -1; while(myArray[++i]){ console.log(myArray[i]) }` — Sherali Turdiyev, Oct 18 '15 at 17:11
Possible duplicate of [Loop through array in JavaScript](http://stackoverflow.com/questions/3010840/loop-through-array-in-javascript) — Max, Oct 18 '15 at 17:26

Ling Zhong · Accepted Answer · 2015-10-18T16:50:37.097

forEach should be the way to go, as part of the Array.prototype functions.

For loop

for (var index = 0; index < myArray.length; index++)
    console.log(myArray[index])

If I had to pick one of the above, vanilla for-loop with length above is the most preferred.

For...in loop

for (var index in myArray)
    console.log(myArray[index]);

You should avoid this at all cost! It's bad practice to mix idioms meant for Object with Array. You may run into buggy iterations through unwanted elements

score 1 · Answer 2 · answered Oct 18 '15 at 16:44

For loop

for (var index = 0; index < myArray.length; index++)
console.log(myArray[index]);

This is the best choice for an array, and crossbrowser ! It will permit to break the loop when you want, but not with a Array.forEach

For in

Avoid this approach with array !

Standard JavaScript practice for iterating through an entire array?

2 Answers2