使用上下文 API 給我未定義

Question

所以我使用 Auth0 進行用戶注冊。 我正在嘗試獲取sub:value下的用戶 ID，以添加到我的數據庫中以識別用戶的帖子。 我正在嘗試使用上下文 API 來獲取用戶信息以放入我的數據庫中。

react-auth0-spa.js

// src/react-auth0-spa.js
import React, { useState, useEffect, useContext } from "react";
import createAuth0Client from "@auth0/auth0-spa-js";


const DEFAULT_REDIRECT_CALLBACK = () =>
  window.history.replaceState({}, document.title, window.location.pathname);

export const Auth0Context = React.createContext();
export const useAuth0 = () => useContext(Auth0Context);
export const Auth0Provider = ({
  children,
  onRedirectCallback = DEFAULT_REDIRECT_CALLBACK,
  ...initOptions
}) => {
  const [isAuthenticated, setIsAuthenticated] = useState();
  const [user, setUser] = useState();
  const [auth0Client, setAuth0] = useState();
  const [loading, setLoading] = useState(true);
  const [popupOpen, setPopupOpen] = useState(false);

  useEffect(() => {
    const initAuth0 = async () => {
      const auth0FromHook = await createAuth0Client(initOptions);
      setAuth0(auth0FromHook);

      if (window.location.search.includes("code=") &&
          window.location.search.includes("state=")) {
        const { appState } = await auth0FromHook.handleRedirectCallback();
        onRedirectCallback(appState);
      }

      const isAuthenticated = await auth0FromHook.isAuthenticated();

      setIsAuthenticated(isAuthenticated);

      if (isAuthenticated) {
        const user = await auth0FromHook.getUser();
        setUser(user);
      }

      setLoading(false);
    };
    initAuth0();
    // eslint-disable-next-line
  }, []);

  const loginWithPopup = async (params = {}) => {
    setPopupOpen(true);
    try {
      await auth0Client.loginWithPopup(params);
    } catch (error) {
      console.error(error);
    } finally {
      setPopupOpen(false);
    }
    const user = await auth0Client.getUser();
    setUser(user);
    setIsAuthenticated(true);
  };

  const handleRedirectCallback = async () => {
    setLoading(true);
    await auth0Client.handleRedirectCallback();
    const user = await auth0Client.getUser();
    setLoading(false);
    setIsAuthenticated(true);
    setUser(user);
  };
  return (
    <Auth0Context.Provider
      value={{
        isAuthenticated,
        user,
        loading,
        popupOpen,
        loginWithPopup,
        handleRedirectCallback,
        getIdTokenClaims: (...p) => auth0Client.getIdTokenClaims(...p),
        loginWithRedirect: (...p) => auth0Client.loginWithRedirect(...p),
        getTokenSilently: (...p) => auth0Client.getTokenSilently(...p),
        getTokenWithPopup: (...p) => auth0Client.getTokenWithPopup(...p),
        logout: (...p) => auth0Client.logout(...p)
      }}
    >
      {children}
    </Auth0Context.Provider>
  );

};

other.js （嘗試從 react-auth0-spa.js 獲取用戶信息）

class AddAlbum extends Component {
  constructor(props) {
    super(props);
 }

componentDidMount() {
    let value = this.context;
    console.log(value);

  }

render() {
    return (
)
}
AddAlbum.contextType = Auth0Context;

這給了我user: undefined

在我的 index.js 我有這個

ReactDOM.render(
  <Auth0Provider
    domain={config.domain}
    client_id={config.clientId}
    redirect_uri={window.location.origin}
    onRedirectCallback={onRedirectCallback}
  >
    <App />
  </Auth0Provider>,
  document.getElementById("root")
);

我相信這給了我這些結果：

所以我想知道為什么我的 Context API 不起作用並給我user: undefined 。

Answer 1

您在組件第一次掛載時記錄用戶，這是在 await auth0FromHook.getUser() 調用完成之前很久。 將它記錄在componentDidUpdate ，或者如果該值可用，則檢查父componentDidUpdate ，並且在它可用之前不要掛載子組件。