Are data structures & algorithms needed for front end developer!

I want to apply for a React js or Front End web developer job but I was wondering in the interview will they ask me and test me about these topics that I mentioned in the title?

That’s very specific of the hiring process of the company you want to work for. Your best bet is to reach out to current engineers there and ask them for the kind of hiring process they do. They most likely won’t be able to tell you specifics, but at least they might give you a hint on the kind of trick questions, algorithms or other topics!

Data structures tend to be very basic anyways, so it would be in your best interest to learn about them even if you don’t think you’ll need them.