How exactly does element.classList.contains() work in JavaScript?

Question

I needed to use element.classList.contains('some-class') to check if an element contains at least one of three classes, so I wrote:

if (element.classList.contains('class1', 'class2', 'class3')) {
  // do stuff here
}

The result was - if the element has 'class1', it returns true, no matter if it has 'class2' or/and 'class3', and // do stuff here executes. However, if it has 'class2' and/or 'class3', it returns false and // do stuff here does not execute.

I worked around it with:

if (element.classList.contains('class1') || element.classList.contains('class2') || element.classList.contains('class3')) {
  // do stuff here 
}

Answer 1

This function only takes one parameter. The contains method is used to check if your classList contains a singular element. The code block that you have posted at the bottom is a good workaround. But unfortunately what you are trying to do at the top is beyond the reach of the classList API.

Answer 2

It tells you if the class name you pass as the first argument is one of the classes the element is a member of.

As with all JavaScript functions, you can pass as many additional arguments are you like. The contains function just doesn't do anything with them.