此表达式不可调用。类型“{}”没有调用签名。TS2349

Question

一个很常见的 TypeScript 错误 TS2349，即sth has no call signatures.

在不同的情况下，它使用不同的变通方法来解决。但是处理反应的上下文，我发现的最佳解决方案是使用// @ts-ignore.

请问，在这种情况下正确的方法是什么？

// auth.tsx

import { CurrentUserContext } from 'components/currentUser';
import React, { useState, useEffect, useContext } from 'react';

const Auth = ({ onLogin }: {onLogin: any}) => {

  const [, setCurrentUserState] = useContext(CurrentUserContext);
  const [credentials, { data }] = useMutation(AUTH);

  ...

  useEffect(() => {
    if (data) {

      // TypeScript Error without @ts-ignore:
      // This expression is not callable.
      // Type '{}' has no call signatures.  TS2349

      // @ts-ignore
      setCurrentUserState((state: any) => ({
        ...state,
        currentUser: data.login.author,
      }))
    }
  }, [data, setCurrentUserState]);

  return <div>{data.login.author}</div>
}

// currentUser.tsx

import React, { createContext, useState } from 'react';

const CurrentUserContext = createContext([{}, () => {}]);

const CurrentUserProvider = ({ children }: {children: any}) => {
  const [state, setState] = useState({
    currentUser: null,
  })
  return (
    <CurrentUserContext.Provider value={[state, setState]}>
      { children }
    </CurrentUserContext.Provider>
  )
};

export {
  CurrentUserContext,
  CurrentUserProvider,
}

nb“反应”：“^16.13.1”“打字稿”：“~3.7.2”

Answer 1

描述并明确指定类型：

type IUserState = {
    currentUser?: object;
};

type ICurrentUserContext = [IUserState, React.Dispatch<React.SetStateAction<IUserState>>];

const CurrentUserContext = React.createContext<ICurrentUserContext>([{}, () => null]);

const CurrentUserProvider = ({ children }: { children: any }) => {
    const [state, setState] = useState<IUserState>({
        currentUser: null,
    });

    return <CurrentUserContext.Provider value={[state, setState]}>{children}</CurrentUserContext.Provider>;
};