Discussion on: React useNavigate faster than useContext

[Muhammet Fatih Gul]

I'm using backend too. So, i don't know if i can use Codesandbox to show my issue. I'll share some codes to indicate my issue

This is my Login page. I'm using "useContext". I created a useEffect to see if user already logged in. authState.status is checking if there's a cookie in the browser in the backend.

When I click "Login button". loginUser() function is working. This function is creating new user. If there's not an error, it changes the state and creating a session. After that its navigate to profile

function Login() {
  let navigate = useNavigate();
  const [email, setEmail] = useState("");
  const [password, setPassword] = useState("");

  //Context
  const { authState, setAuthState } = useContext(AuthContext);

  console.log(authState.status);
  useEffect(() => {
    if (authState.status == true) {
      navigate("/profile");
    }
  }, []);

  // const [loginStatus, setLoginStatus] = useState("");

  Axios.defaults.withCredentials = true;

  const loginUser = () => {
    Axios.post("http://localhost:3001/login", {
      email: email,
      password: password,
    }).then((response) => {
      if (response.data.message) {
        console.log(response.data.message);
      } else {
        setAuthState({
          email: response.data.email,
          id: response.data.id,
          status: true,
        });
        navigate("/profile");
      }
    });
  };
  return (

This is my App.js. In useEffect, I'm making a get request to /login to checking if there's a cookie in the browser in the backend. app.post and app.get are totally different things in the backend

function App() {
  const [authState, setAuthState] = useState({
    email: "",
    id: 0,
    status: false,
  });

  useEffect(() => {
    Axios.get("http://localhost:3001/login", { withCredentials: true }).then(
      (response) => {
        console.log(response);
        if (response.data.message) {
          setAuthState({ ...authState, status: false });
          console.log(response.data.message);
        } else {
          setAuthState({
            email: response.data[0].email,
            id: response.data[0].id,
            status: true,
          });
          console.log("I'm here");
        }
      }
    );
  }, []);

  return (

this is app.get

app.get("/login", (req, res) => {
  if (req.session.user) {
    // res.send({ user: req.session.user });
    res.json(req.session.user);
  } else {
    res.send({ message: "It's Empty" });
  }
});

I'm sorry if it is too much ask :(

My issue is. When i go to Profile in the first time. I have to refresh the page to see the email from the context

[Jacob Gavin]

In you App.js you aren't setting the same auth state as you do in you Login component. It seems that you have missunderstood the concept of context a bit. Or there are some important bits of code missing here. You need to create a "AuthProvider" that stores your context. And you can handle the login and the "check auth cookie" request in that Provider instead of doing it in different parts of the app.

I can't really point you in the right correction based on this. I recommend reading kentcdodds.com/blog/authentication... to get some understanding of how it can be done.

Is your app.get("/login", ...) function only returning what got passed in req.session.user or have you stripped out some logic there?

Also this useEffect needs to have authState.status in its dependency array like this:

  useEffect(() => {
    if (authState.status == true) {
      navigate("/profile");
    }
  }, [authState.status]);

otherwise it will only check that status on initial render. You can read about it here reactjs.org/docs/hooks-reference.h...

[Muhammet Fatih Gul]

Yess. I already have an AuthContext.Provider in App.js and I imported it

<div className="App">
      <AuthContext.Provider value={{ authState, setAuthState }}>
        <Router>
          <Header />
          <Routes>
            <Route exact path="/" element={<Mainpage />} />
            <Route exact path="/login" element={<Login />} />
            <Route exact path="/register" element={<Register />} />
            <Route path="/profile" element={<Profile />} />
            <Route path="/courses" />
          </Routes>
        </Router>
      </AuthContext.Provider>
    </div>

app.get is just returning req.session.user. I created it in app.post('/login'). Here it is

app.post("/login", (req, res) => {
  const email = req.body.email;
  const password = req.body.password;

  db.query("SELECT * FROM users WHERE email = ?;", email, (err, result) => {
    if (err) {
      res.send({ err: err });
    }

    if (result.length > 0) {
      bcrypt.compare(password, result[0].password, (error, response) => {
        if (response) {
          req.session.user = result;
          // console.log("hello: " + req.session.user);
          res.send(result);
        } else {
          res.send({ message: "Wrong username/password combination!" });
        }
      });
    } else {
      res.send({ message: "User doesn't exist" });
    }
  });
});

Thank you for the tips and the sources. I will check immediately