Using forEach method in javascript

Question

Is forEach method designed to work for only array in javascript?Can anyone share idea or an example on what major task can be completed with forEach() method or is it useful for only getting element value and index?

• Henrik Andersson: developer.mozilla.org/en-US/docs/JavaScript/Reference/… - would be the best start for you

Answer 1

No.

It is designed to work on arrays, but can operate on any array-like object (although you still have to access it from somewhere where it exists).

For example, on a NodeList:

Array.prototype.forEach.call(
 document.getElementsByTagName('div'), 
 function (divElement) { console.log(divElement); }
);

• Denys Séguret: Try "abc".forEach(function(v){console.log(v)}). You'd have to use apply or call.
• Quentin: @dystroy — Yes, you have to use apply or call. That doesn't mean you can't use it.
• Denys Séguret: @Quentin I agree (and I didn't downvote). I simply think this should be clearer.
• Maizere Pathak.Nepal: @Quentin i agree too, with the use of call and apply it works but is it only for Nodelist?
• nnnnnn: @Maizere - No, any array-like object, e.g., it would work on this object: {"0":10,"1":20,"length":2}.

Answer 2

It is an Array function. See documentation

You can use it on any array-like object but it's not very convenient because you have to use apply or call. For example :

[].forEach.call("abc",function(v){console.log(v)})

To iterate over objects keys, you should use for..in :

for (key in object) {
 var value = object[key];
} 

Note that jQuery's compatibility function $.each enables the same iteration function for both arrays and non array objects but you generally know if you're dealing with an array (or you should) so I'd use it only for compatibility with old browsers.

• Henrik Andersson: Just for good reading as well! stackoverflow.com/questions/500504/…

Answer 3

The forEach method in JavaScript allows you to traverse an array and apply a particular action to each of its elements through a function. Let's see an example:

array.forEach(function(elementoActual, indice, array))

elmentoActual: es el valor del elemento actual del array. índice: es el índice del elemento actual del array (opcional). array: es el array que se está recorriendo (opcional).

For more information I leave the following article https://4geeks.com/es/how-to/metodo-foreach-javascript

• Bergi: Did you mean to post to Stack Overflow en español?
• Phake: Code formatting