Navigating Next.js: Mastering the art of localStorage Access

Question

Navigating Next.js: Mastering the art of localStorage Access

Currently, I am developing my first member area using next.js. My goal is to store some data in localStorage (such as token, expiresAt, userInfo), which will eventually be moved to an http-only cookie.

The code below is generating the error: "LocalStorage is not defined":

const AuthProvider = ({ children }) => {
   
   const token = localStorage.getItem("token");
   const userInfo = localStorage.getItem("userInfo");
   const expiresAt = localStorage.getItem("expiresAt");
   

  const [authState, setAuthState] = useState({
    token,
    expiresAt,
    userInfo: userInfo ? JSON.parse(userInfo) : {},
  });

  const setAuthInfo = ({ token, userInfo, expiresAt }) => {
    localStorage.setItem("token", token);
    localStorage.setItem("userInfo", JSON.stringify(userInfo));
    localStorage.setItem("expiresAt", expiresAt);

    setAuthState({
      token,
      userInfo,
      expiresAt,
    });
  };

I have attempted to resolve it by implementing the following snippet:

if (typeof window !== 'undefined') {
const token = localStorage.getItem("token");
const userInfo = localStorage.getItem("userInfo");
const expiresAt = localStorage.getItem("expiresAt");}

However, this resulted in the error message "token is undefined". I then tried declaring the variables const token, const userInfo, and const expiresAt globally, but encountered the error: "Unexpected token o in JSON at position 1".

I am struggling with this issue and would appreciate any assistance. Thank you!

javascript authentication local-storage next.js

Answer 1

Answer №1

After tinkering around with the code a bit more and thanks to the assistance of fellow developers, I finally cracked the solution:

const AuthProvider = ({ children }) => {
  let token = "";
  let userInfo = "";
  let expiresAt = "";

  if (typeof window !== "undefined") {
    token = localStorage.getItem("token");
    userInfo = localStorage.getItem("userInfo");
    expiresAt = localStorage.getItem("expiresAt");
  }

...

The conditional statement ensures that the code only runs when the window is accessible. Additionally, I had to declare the variables (let token, let expiresAt, and let userInfo) outside of the conditional statement so they could be accessed in other parts of the code.

This tip might come in handy for someone facing a similar issue.

Answer 2

After tinkering around with the code a bit more and thanks to the assistance of fellow developers, I finally cracked the solution:

const AuthProvider = ({ children }) => {
  let token = "";
  let userInfo = "";
  let expiresAt = "";

  if (typeof window !== "undefined") {
    token = localStorage.getItem("token");
    userInfo = localStorage.getItem("userInfo");
    expiresAt = localStorage.getItem("expiresAt");
  }

...

The conditional statement ensures that the code only runs when the window is accessible. Additionally, I had to declare the variables (let token, let expiresAt, and let userInfo) outside of the conditional statement so they could be accessed in other parts of the code.

This tip might come in handy for someone facing a similar issue.

Answer 3

Answer №2

Here is a solution that should be effective

if (typeof window !== 'undefined') {
  let accessToken = localStorage.getItem("accessToken");
  let userCredentials = localStorage.getItem("userCredentials");
  let expirationTime = localStorage.getItem("expirationTime");
}

If you're encountering the error accessToken is not defined or unexpected character, it may be due to either the absence of the key accessToken in your localStorage or incorrect data assignment.

Answer 4

Here is a solution that should be effective

if (typeof window !== 'undefined') {
  let accessToken = localStorage.getItem("accessToken");
  let userCredentials = localStorage.getItem("userCredentials");
  let expirationTime = localStorage.getItem("expirationTime");
}

If you're encountering the error accessToken is not defined or unexpected character, it may be due to either the absence of the key accessToken in your localStorage or incorrect data assignment.

Answer 5

Answer №3

useEffect hook specifically runs on the client side, ensuring that storage is defined when accessed inside of it. Take advantage of this custom hook to handle storage functionality:

export default function useStorage(key, type = "sessionStorage") {
  const [value, setValue] = useState();

  // Retrieve initial data from storage
  useEffect(() => {
    const storage = type === "sessionStorage" ? sessionStorage : localStorage;
    setValue(storage.getItem(key));
  }, [key, type]);

  // Save data to storage
  useEffect(() => {
    // Avoid overwriting existing value during first render
    if (value !== undefined) {
      const storage = type === "sessionStorage" ? sessionStorage : localStorage;
      storage.setItem(key, value);
    }
  }, [key, value, type]);

  return [value, setValue];
}

Usage Example:

const [myValue, setMyValue] =  useStorage("my_value")

Answer 6

useEffect hook specifically runs on the client side, ensuring that storage is defined when accessed inside of it. Take advantage of this custom hook to handle storage functionality:

export default function useStorage(key, type = "sessionStorage") {
  const [value, setValue] = useState();

  // Retrieve initial data from storage
  useEffect(() => {
    const storage = type === "sessionStorage" ? sessionStorage : localStorage;
    setValue(storage.getItem(key));
  }, [key, type]);

  // Save data to storage
  useEffect(() => {
    // Avoid overwriting existing value during first render
    if (value !== undefined) {
      const storage = type === "sessionStorage" ? sessionStorage : localStorage;
      storage.setItem(key, value);
    }
  }, [key, value, type]);

  return [value, setValue];
}

Usage Example:

const [myValue, setMyValue] =  useStorage("my_value")

Answer 7

Answer №4

Implementing localStorage functionality in Next JS 13

Discover how to manage localStorage operations like creating, updating, and removing tokens in Next JS with ease.

const [accessToken, setAccessToken] = useState(null);

useEffect(() => {
  if (typeof window !== "undefined" && window.localStorage) {
    let token = localStorage.getItem("access_token");
    setAccessToken(token);
  }
}, [setAccessToken]);

const createAccessToken = (newToken) => {
  if (typeof window !== "undefined" && window.localStorage) {
    localStorage.setItem("access_token", newToken);

    let token = localStorage.getItem("access_token");

    setAccessToken(token);
  }
};

const removeAccessToken = () => {
  if (typeof window !== "undefined" && window.localStorage) {
    localStorage.removeItem("access_token");
    setAccessToken(null);
  }
};

const logoutUser = useCallback(() => {
  removeAccessToken();
}, []);

Additional Resources

Answer 8

Implementing localStorage functionality in Next JS 13

Discover how to manage localStorage operations like creating, updating, and removing tokens in Next JS with ease.

const [accessToken, setAccessToken] = useState(null);

useEffect(() => {
  if (typeof window !== "undefined" && window.localStorage) {
    let token = localStorage.getItem("access_token");
    setAccessToken(token);
  }
}, [setAccessToken]);

const createAccessToken = (newToken) => {
  if (typeof window !== "undefined" && window.localStorage) {
    localStorage.setItem("access_token", newToken);

    let token = localStorage.getItem("access_token");

    setAccessToken(token);
  }
};

const removeAccessToken = () => {
  if (typeof window !== "undefined" && window.localStorage) {
    localStorage.removeItem("access_token");
    setAccessToken(null);
  }
};

const logoutUser = useCallback(() => {
  removeAccessToken();
}, []);

Additional Resources

Answer 9

Answer №5

If you're looking to enhance the functionality of your project, one suggestion is to incorporate the AuthProvider component through dynamic imports with the ssr option set to false. Here's an example:

const AuthProvider = dynamic(() => import("AuthProvider.tsx"), {ssr:false})

Once imported dynamically, you can utilize the AuthProvider as needed throughout your application. This approach has proven successful for me in similar scenarios.

Answer 10

If you're looking to enhance the functionality of your project, one suggestion is to incorporate the AuthProvider component through dynamic imports with the ssr option set to false. Here's an example:

const AuthProvider = dynamic(() => import("AuthProvider.tsx"), {ssr:false})

Once imported dynamically, you can utilize the AuthProvider as needed throughout your application. This approach has proven successful for me in similar scenarios.

Navigating Next.js: Mastering the art of localStorage Access

Answer №1

Answer №2

Answer №3

Answer №4

Implementing localStorage functionality in Next JS 13

Answer №5

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