Async TypeScript
Lesson
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Promise types

Promises in TypeScript have a type parameter for the resolved value.

index.ts
// Promise that resolves to string
const fetchName = (): Promise<string> => {
  return Promise.resolve("Alice");
};

// Promise that resolves to User
const fetchUser = (): Promise<User> => {
  return fetch("/user").then(r => r.json());
};
📦

A promise of typed data