Meta Software Engineer interview questions

(Front End Developer) After going to a conference, and talking with several people from Facebook who also attended, I was contacted via email to see if I was interested in doing an interview. I said yes, and got my first phone interview a few days later. In a shared code environment I needed to do a recursion assignment, and also create a polyfill. It went okay, although I wasn't happy with my performance on the polyfill. This took about 40 minutes. The more surprised I was that they asked me for a second phone interview, whereby I also had to do a recursion question. I made it harder then necessary for myself, which was unfortunate. After this I was invited to Facebook HQ, and had to do 4 interviews. Interviews were about recursion, closures, css, implementations. Unfortunately I wasn't good enough for Facebook, so that got me messed up for a month or so. I thought I did pretty good, but needed too much time to get going. The recruiters and interviewers were great. The process went really smooth, and comfortable.

Fairly standard. 4 technical rounds and 1 phone interview in a period of 2-3 weeks. NDA got my hands tied.