LLD: video player and file uploader + LLD: in-memory cache, pub-sub and parking-lot style questions
Comes up in: Low-level design, Frontend system design
This concept is being written. It gets the full five steps — explanation, predict, interview angle, practice with tests, and review cards. Here is exactly what it will cover, so you can study it elsewhere in the meantime.
What it covers
- player state machine (idle/loading/playing/buffering/error)
- controls as components
- uploader with chunking, resumable uploads, progress, concurrency limit, retry
- generic LLD questions occasionally asked in frontend loops (cache with policies, rate limiter, elevator/parking lot) approached in TypeScript
- how to present classes, relationships and extensions in 45 minutes
Words you will know
What you will practise
- uploader class with tests
- cache with pluggable eviction policies
Interview questions this answers
- Design a resumable file uploader.
- Design a cache that supports LRU and LFU eviction.