Why doesn't .includes() work with .classList?

Question

element.classList returns an array of classes, its my understanding .includes() is used with arrays, so I don\'t understand why this wont work, I k

Answer 1

The reason includes doesn't work is due to classList not being an array, but an array-like object. In this case it is a DOM Token List.

You can convert an array-like object to an array by using the following:

var liClasses = [].slice.apply(li.classList);

or

var liClasses = [...li.classList]; // es2015 syntax

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Otherwise, .includes() should be .contains(). See https://developer.mozilla.org/en-US/docs/Web/API/Element/classList

li.classList.contains('main-nav')

contains( String )

Checks if specified class value exists in class attribute of the element.