Build a Real-time Chat App with React, Node.js, and Socket.io

Table of Contents

1. Introduction
2. Logging In a User
3. Creating a HTTP Request
4. Adding User to State and Local Storage
5. Handling Error in Login
6. Updating Login Info from Form
7. Submitting Login
8. Handling Loading Status
9. Rendering Error Messages
10. Conclusion

Logging In a User

To log in a user, we need to perform a HTTP request to our endpoint and add the user to the state and local storage. In this episode, we will dive right in and see how we can accomplish this.

Creating a HTTP Request

To perform the HTTP request, we have already created a service called postRequest. We will now Create a function called loginUser in the auth Context. This function will be similar to the registerUser function. We will also need to handle the login info, which contains the email and password.

Adding User to State and Local Storage

After performing the HTTP request, we need to update the state with the user information. We also need to save the user to the local storage. This can be done using the localStorage.setItem() method. We will stringify the user object before saving it as a JSON string.

Handling Error in Login

Just like we handled the error in the registration process, we need to handle errors in the login process as well. We will add the loginError state and the isLoginLoading state. If an error occurs, we will set the loginError state to the error message. Otherwise, we will set the user to the state and save it to the local storage.

Updating Login Info from Form

To correctly update the login info from our form, we will create a function called updateLoginInfo. This function will be similar to the updateRegisterInfo function. It will update the login info state by spreading the login info object.

Submitting Login

To submit the login form, we will use the onSubmit event. When the submit button is clicked, it will call the loginUser function. This function will make the HTTP request to the backend and handle the response.

Handling Loading Status

While the login process is in progress, we want to Show a loading status to the user. We will use the isLoginLoading state to conditionally render the loading message. When the login process is complete, we will set the isLoginLoading state back to false.

Rendering Error Messages

If any error occurs during the login process, we want to display the error message to the user. We will conditionally render the error message using the loginError state.

Conclusion

In this episode, we learned how to log in a user by performing a HTTP request, updating the state and local storage, handling errors, and rendering messages. We also implemented form validation and a loading status indicator. With these features in place, our login functionality is complete.

Highlights

• Logging in a user with a HTTP request
• Updating state and local storage
• Handling errors and rendering error messages
• Implementing loading status indicator
• Form validation for login

FAQ

Q: Can I log in multiple users at the same time? A: No, our system currently supports logging in only one user at a time.

Q: How long does it take to log in a user? A: The login process is usually very fast, usually taking a few seconds depending on the network connection.

Q: Can I retrieve the login information later? A: Yes, the login information is stored in the local storage, so you can retrieve it later if needed.

Q: What happens if I enter an incorrect password? A: If you enter an incorrect password, you will receive an error message indicating that the password is invalid.

Q: Can I log in using social media accounts? A: No, our system currently only supports logging in using email and password credentials.