Interview Experience for SDE 2 Frontend at PW (PhysicsWallah)

Joined the Director of Engineering to interview.

More like a culture-fit round. Asked some scenario-based questions and what are my expectations when I work in a team.

Interviewer was an EM and gave the challenge to design a frontend system for Google Meet. Interviewer was keen on,
- UI Components Architecture & Data flow
- What kind of states (data structures used)
- Discussion on networks (Websockets vs WebRTC)

1. First Challenge, given a Holy Grail (not exact) like UI layout and asked to rearrange elements to the expected design using only CSS.
2. Design Frontend System Design for a live-stream based Chat like YouTube or Zoom Classroom.
- Had to design & give implementation details considering React Architecture.
- Hard parts of this problem is understanding the states used & its structure & also rendering UI in an optimized way despite stream of messages received.

Asked to implement 2 JavaScript problems.
1. Implement Throttling promises by batching
2. Implement Promise.all polyfill

I had some basic System Design questions, specifically based on real-time streaming, as both the Interviewer and I had experience working on such products.
1. How do you maintain good streaming quality in low network conditions?
2. What strategies to use for performance if the main thread is busy decoding streaming data?