Be ready with the Big O complexities and the approaches to optimize the same. It's not the framework level questions/tech stack that matters, but the in general Javascript knowledge, problem-solving questions, whiteboard puzzles, and "capacity specific questions" and reasoning questions. ( The Shakuntala Devi puzzles kind of ). I was prepared for Angular / react level questions as I was from a Front end field and the position interviewed for was also the same. But there was very little being asked.