Meta Front End Engineer interview questions

I was reached out by a recruiter on LinkedIn for a Software Engineer role, then later referred to a different recruiter who's in charge of recruiting Front End Engineers after they learned more about my experience and interest. The process consisted of 2 phone screens, to complete 2 questions in a 45 min session for each, once I came up with a working solution, interviewers asked me to implement any optimizations and analyze the runtime of my code. The onsite consisted of 4 sessions, 2 coding rounds, 1 behavioral round with an engineering manager, and then 1 round on front end system design and architecture, I enjoyed the design round the most as it was very free-form and carried out much like you'd discuss with your coworkers during day-to-day work. The coding rounds were very javascript heavy, the first round was mainly testing your understanding of timeouts, prototypes, the DOM, and your knowledge about different javascript collections. The second coding round was an algorithm and data structure problem with a front end slant, you need to have a good understanding of the DOM. The behavioral round was rather standard and casual, the manager will try to assess your past experience and motivation, and you also get to ask a lot of questions in this round. The hiring committee was fairly quick to decide that I can be moved on to the offer stage, but the actual offer itself took a few weeks to send out. The recruiter has been very friendly and helpful, and overall the recruiting process has been a positive experience.

I got an introductory email from the recruiter in Facebook London office. I submitted my resume and answered a couple of questions via email and had a short phone interview with a HR officer. A couple of weeks later, I had a technical coding interview with a software engineer.