TypeScript tutorialLesson 29Free preview

TS Mapped Types

This lesson is part of TypeScript · All levels

Summary

Mapped types build new types by iterating the properties of other types using the [K in Keys] pattern. You can add a readonly or optional modifier, even replace the key name with the as clause. This technique forms the basis of many of the built-in TypeScript utility types.

Key points

Mapped type using [K in Keys]: T
Modifier readonly and can be applied
Clause as changes the name of the key

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