When would you pick interface over type?
PICTURE THIS: GIT FLOW
Simple meaning
I pick interface for object shapes that might be extended or merged in declaration files.
WHY — TypeScript instead of guessing?
Why interviewers care about TypeScript:
on TypeScript.
the situation, the default choice, and one exception - that reads as experience.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1I pick interface for
object shapes that might be extended or merged in declaration files.
- 2I pick type for
unions, intersections of primitives, and mapped results.
- 3How it works
Both can describe component props
- 4consistency on the team
matters more than dogma.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
I pick interface for object shapes that might be extended or merged in declaration files. I pick type for unions, intersections of primitives, and mapped results.