How to use if on a specific string

I want to use an if statement to see if something has hidden written in it. The div classname is ".title-button" and I want to use in javascript or jquery if {.title-button = "Hidden"){...} but it doesn't work.

This is for a side project of mine. I have researched it lots of time but I cant find anything

if(".title-button" = "hidden"){
}

is the only code I have, but it doesn't work.

My expected result is to be able to check the string in the class, I don't get an actual result.