NodeList.prototype.forEach()

callback

A function to execute on each element of someNodeList. It accepts 3 parameters:

currentValue

The current element being processed in someNodeList.

currentIndex Optional

The index of the currentValue being processed in someNodeList.

listObj Optional

The someNodeList that forEach() is being applied to.

thisArg Optional

Value to use as this when executing callback.

undefined.

let node = document.createElement("div");
let kid1 = document.createElement("p");
let kid2 = document.createTextNode("hey");
let kid3 = document.createElement("span");

node.appendChild(kid1);
node.appendChild(kid2);
node.appendChild(kid3);

const list = node.childNodes;

list.forEach(
  function(currentValue, currentIndex, listObj) {
    console.log(currentValue + ', ' + currentIndex + ', ' + this);
  },
  'myThisArg'
);

The above code results in the following:

[object HTMLParagraphElement], 0, myThisArg
[object Text], 1, myThisArg
[object HTMLSpanElement], 2, myThisArg

This polyfill adds compatibility to all Browsers supporting ES5:

if (window.NodeList && !NodeList.prototype.forEach) {
    NodeList.prototype.forEach = function (callback, thisArg) {
        thisArg = thisArg || window;
        for (var i = 0; i < this.length; i++) {
            callback.call(thisArg, this[i], i, this);
        }
    };
}

OR

if (window.NodeList && !NodeList.prototype.forEach) {
   NodeList.prototype.forEach = Array.prototype.forEach;
}

The above behavior is how many browsers actually implement NodeList.prototype.forEach() (Chrome, for example).

• Polyfill of NodeList.prototype.forEach in core-js
• Node
• NodeList