扩大打字稿中反应类型的问题

Question

I'm trying to add the new hooks to react in typescript (last I checked, they weren't available on DefinitelyTyped), but it's not working.

I've made a file types/react.d.ts that looks like this:

import React from 'react';

declare module 'react' {
  function useState<T>(
    initialState: T | (() => T),
  ): [T, (newState: T | ((oldState: T) => T)) => void];
}

but when I try to use it, it's not working.

Answer 1

You could refer to the Flow types for React Hooks here - https://github.com/facebook/flow/pull/7149/

They should be pretty similar to TypeScript.

In Flow, it looks like:

declare type BasicStateAction<S> = (S => S) | S;
declare type Dispatch<A> = A => void;

declare export function useState<S>(
  initialState: (() => S) | S,
): [S, Dispatch<BasicStateAction<S>>];

Answer 2

事实证明，问题与Matt McCutchen建议的tsconfig.json配置有关。