LESSON 3.1
Conditional types and infer
Learn key techniques and workflows in TypeScript for Application Developers.
14m
intermediate
15,256 students
Overview
A conditional type branches on assignability, and infer pulls a type out of the branch it matched. This is how utility types are built.
In this lesson you will:
- Branch a type on an extends check
- Extract inner types with infer
- Understand distribution over union members
Pro Tip
Use caching and revalidation wisely to ensure your app stays fast and data remains fresh without unnecessary requests.