Sometimes, we want to fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript.
In this article, we’ll look at how to fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript.
How to fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript?
To fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript, we can use the spread operator to convert the node list returned by getElementsByClassName
to an array.
For instance, we write
[...document.getElementsByClassName("myClass")].forEach((v) => {
//...
});
to get the elements with class myClass
with getElementsByClassName
.
Then we spread the entries in the node list returned by getElementsByClassName
into an array.
Next, we call forEach
with a callback to loop through each element.
Conclusion
To fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript, we can use the spread operator to convert the node list returned by getElementsByClassName
to an array.