TypeScript with React's useContext? property does not exist-CodePudding

Trying to use TypeScript with React's useContext. Thought I had it figured out but get an error stating that the props do not exist when I destructure the custom hook.

Here's my custom hook - no TypeScript errors from what I see

type AppContext = {
  handleLogin: HandleLogin;
};

type HandleLogin = (email: string, password: string) => void;

const AuthContext = createContext<AppContext | null>(null);

export const AuthProvider = ({ children }: { children: React.ReactNode }) => {
  const [user, setUser] = useState(null);

  const router = useRouter();

  // Handle login
  const handleLogin: HandleLogin = async (email: string, password: string) => {
    const userData = await login(email, password);
    setUser(userData);
  };

  return (
    <AuthContext.Provider value={{ handleLogin }}>
      {children}
    </AuthContext.Provider>
  );
};

But when I destructure the hook like so...

  const { handleLogin } = useAuth();

I get the following error - * Property 'handleLogin' does not exist on type 'AppContext | null'.*

I get the same error if I include another value or function within the context's value but run into the same error. Really not sure what I'm missing.

CodePudding user response：

You're assigning the initial value of context as null, so you need to make sure the context is not null when you're restructuring. Or you can tell typescript that context will always be AppContext.

const AuthContext = createContext<AppContext>({} as AppContext);

It's type-safe because the value will be set on the Provider when your component uses the context.