Be ready to explain: structural typing, narrowing, generics, unknown vs any, utility types, and how strict flags change behavior.
Answer structure
- One-sentence definition
- Concrete example
- Trade-off or when not to use it
Top ten prompts
- Structural vs nominal typing
interfacevstype- Narrowing techniques
- Generics and variance (high level)
unknownvsany- Utility types: Pick/Omit/Partial
- What
strictenables - How TS compiles (erase types)
- Runtime validation at boundaries
- Module resolution basics
Self-check
- Practice a 30-second answer for “What is TypeScript?”
Challenge
30-second pitch
- Without notes, explain structural typing in 30 seconds.
- List three strict flags you keep enabled.
Done when: you can answer both aloud clearly.
Interview prep
- How do you explain structural typing?
TypeScript compares shapes, not names—if it has the required properties, it matches.