Pretty sure I use find the most but the others are good to know too.

.includes() method is definitely my favorite way of checking if array contains a value, it makes code that much more readable.

indexOf() is the "old way" of doing it because includes() is only supported in IE Edge 14+ (no IE11 support).

But when targeting modern browsers, or a transpiler or node.js - includes() is the way to go.

Fun fact - you can also use it on strings to check if string includes a value too:

"Does foobar".includes("foo")
// true

Great post!

I think you may have made a typo by accident here:

cost role = 'user';

I love these kind of posts 👊! A good follow up would be an Array with Objects 😉