Topics
Types & Interfaces
Primitive types, object types, interfaces vs type aliases.
Generics
Generic functions, classes, and constraints.
Utility Types
Partial, Required, Pick, Omit, Record, and more.
Type Narrowing
typeof, instanceof, discriminated unions, type guards.
◆ Key Distinction
interface is open (can be merged/extended). type is closed but more expressive (unions, intersections, mapped types). Prefer interface for object shapes, type for everything else.💡 Interview Tip
Know the difference between structural typing (TypeScript) and nominal typing (Java/C#). TS uses structural — if it has the right shape, it’s compatible.