I'm trying to make a simple loop:
const parent = this.el.parentElement
console.log(parent.children)
parent.children.forEach(child => {
console.log(child)
})
But I get the following error:
VM384:53 Uncaught TypeError: parent.children.forEach is not a function
Even though parent.children logs:
What could be the problem?
Note: Here's a JSFiddle.
The parent.children is an Array like object. Use the following solution:
const parent = this.el.parentElement;
Array.prototype.forEach.call(parent.children, child => {
console.log(child)
});
The parent.children is NodeList type, which is an Array like object because:
length property, which indicates the number of nodes{0: NodeObject, 1: NodeObject, length: 2, ...}See more details in this article.
parent.children is an HTMLCollection: which implements the iterable protocol. In an ES2015 environment, you can use the HTMLCollection with any construction that accepts iterables.
Use HTMLCollection with the spread operatator:
const parent = this.el.parentElement;
[...parent.children].forEach(child => {
console.log(child);
});
Or with the for..of cycle (which is my preferred option):
const parent = this.el.parentElement;
for (const child of parent.children) {
console.log(child);
}
parent.children is not an array. It is HTMLCollection and it does not have forEach method. You can convert it to the array first. For example in ES6:
Array.from(parent.children).forEach(child => {
console.log(child)
});
or using spread operator:
[...parent.children].forEach(function (child) {
console.log(child)
});
Array.from(selected_rows).forEach(item => console.log(item)); in my case and it worksA more naive version, at least you're sure that it'll work on all devices, without conversion and ES6 :
const children = parent.children;
for (var i = 0; i < children.length; i++){
console.log(children[i]);
}
parent.children will return a node list list, technically a html Collection. That is an array like object, but not an array, so you cannot call array functions over it directly. At this context you can use Array.from() to convert that into a real array,
Array.from(parent.children).forEach(child => {
console.log(child)
})
parent.children is a HTMLCollection which is array-like object. First, you have to convert it to a real Array to use Array.prototype methods.
const parent = this.el.parentElement
console.log(parent.children)
[].slice.call(parent.children).forEach(child => {
console.log(child)
})
You can check if you typed forEach correctly, if you typed foreach like in other programming languages it won't work.
There is no need for the forEach, you can iterate using only the from's second parameter, like so:
let nodeList = [{0: [{'a':1,'b':2},{'c':3}]},{1:[]}]
Array.from(nodeList, child => {
console.log(child)
});
Array.from converts the object given in the first parameter into an array. The result is the same as in madox2's answer without needing an extra forEach loop (Array.from MDN docs).If you are trying to loop over a NodeList like this:
const allParagraphs = document.querySelectorAll("p");
I highly recommend loop it this way:
Array.prototype.forEach.call(allParagraphs , function(el) {
// Write your code here
})
Personally, I've tried several ways but most of them didn't work as I wanted to loop over a NodeList, but this one works like a charm, give it a try!
The NodeList isn't an Array, but we treat it as an Array, using Array. So, you need to know that it is not supported in older browsers!
Need more information about NodeList? Please read its documentation on MDN.
That's because parent.children is a NodeList, and it doesn't support the .forEach method (as NodeList is an array like structure but not an array), so try to call it by first converting it to array using
var children = [].slice.call(parent.children);
children.forEach(yourFunc);
Since you are using features of ES6 (arrow functions), you may also simply use a for loop like this:
for(let child of [{0: [{'a':1,'b':2},{'c':3}]},{1:[]}]) {
console.log(child)
}str_json = JSON.parse(array);
str_json.forEach(function (item, index) {
console.log(item);
});
You can use childNodes instead of children, childNodes is also more reliable considering browser compatibility issues, more info here:
parent.childNodes.forEach(function (child) {
console.log(child)
});
or using spread operator:
[...parent.children].forEach(function (child) {
console.log(child)
});
for object try this:
Object.keys(yourObj).forEach(key => {
console.log(key, yourObj[key]);
});
