NodeList Javascript type

Note: this is a followup to “Get links in page without using jQuery”, where I posted a snippet of code that didn’t work…

If you use vanilla Javascript methods like querySelectorAll beware that the returned type is gonna be a NodeList rather than an Array like you, or at least I, would have expected.

A NodeList is a collection of nodes. Derp.

It behaves very much like an Array, but we can’t call forEach or map on it. The reason for this is that this type prototype chain doesn’t include Array.

There are some workarounds to use forEach on a NodeList, but I rather go with an old classic:

var external_links = document.querySelectorAll('a:not([href^="#"])');
for (var i = 0; i < external_links.length; i++) {
   external_links[i].setAttribute("target", "_blank");  
}