TypeScript Interview - Advanced Level
For senior developers with 4+ years of TypeScript experience. Master type system internals, conditional types, template literals, advanced patterns, and type-level programming.
35-45 minutes
4+ years of TypeScript experience
Who is this for?
Senior TypeScript engineers
Technical leads and architects
Library/framework authors
Those preparing for senior/staff roles
What you'll practice
Understanding type system internals
Creating conditional types
Using template literal types
Building advanced mapped types
Type-level programming
Architecting type-safe libraries
Topics covered
Type System Internals
Structural typing
Variance (covariance, contravariance)
Type compatibility
Type widening and narrowing
Advanced Type Manipulation
Conditional types
Template literal types
Mapped types with key remapping
Recursive types
Type Inference
infer keyword
ReturnType and Parameters implementation
Distributive conditional types
Type extraction patterns
Advanced Patterns
Brand types (nominal typing)
Builder pattern with types
Type-safe state machines
Module augmentation
Example questions
Q:
Explain how structural typing works in TypeScript
Q:
What are conditional types and how do you use infer?
Q:
How do template literal types work?
Q:
What is variance and how does it affect type safety?
Q:
How would you implement a type-safe builder pattern?
Q:
How do mapped types with key remapping work?
Preparation tips
Study type system internals
Master conditional types thoroughly
Learn template literal types
Practice type-level programming
Build type-safe libraries
Understand compilation performance implications
Continue your journey
Free • No signup required • AI-powered