Metamask: How to detect if user account on Metamask is logged out in frontend

Here’s an article on detecting disconnected users on your MetaMask wallet in your interface:

Detecting Disconnected Users on MetaMask Wallet: A Guide for Web3 Applications

As a web developer building a web3 application, you’re probably aware of the importance of authenticating users and tracking changes to their account. One key aspect is detecting when a user’s MetaMask account has been disconnected or changed. In this article, we’ll walk you through the steps to detect disconnections on your interface.

Why Detect Disconnected Users?

Before we dive into the solution, let’s review why disconnection detection is important:

• Security: When a user disconnects from their wallet, they lose access to their funds and sensitive information. Tracking disconnections helps you ensure that users can recover their accounts if necessary.

• User Experience: Disconnection alerts notify your users of changes to their accounts, reducing the likelihood of frustration or confusion.

• Debug: Disconnection detection allows for more efficient error handling and recovery processes.

Detecting disconnected users on MetaMask

To detect disconnected users on MetaMask in your interface, you can use a combination of JavaScript events and web3 libraries. Here is an example implementation:

const metamaska ​​​​= window.ethereum; // Retrieve MetaMask instance
// Define event listeners for account changes
metamask.on("change", (account) => {
console.log(Account changed to: ${account.address});
});
// Disconnection event listener
metamask.on("disconnect", () => {
console.log("User disconnected from their wallet.");
});
// Function to check if the user is connected or not
function isConnected() {
return metamask.isAddressOrKey;
}
// Usage example:
if (isConnected()) {
// User is connected, do something...
} else {
// User is disconnected, display a message on the interface.
console.log("User has disconnected from their wallet. Please reconnect.");
}

Alternative solution using web3 library

If you prefer a more robust solution, consider using a web3 library such as Web3.js or Walletify. These libraries provide built-in event listeners for account changes and disconnections:

const Web3 = require ("web3");
const web3 = new Web3(window.ethereum);
// Define event listener functions for account changes and disconnections
web3.on("change", (account) => {
console.log(Account changed to: ${account.address});
});
web3.on("disconnect", () => {
console.log("User disconnected from their wallet.");
});
// Usage example:
if (web3.isAddressOrKey) {
// User is connected, do something...
} else {
// User disconnected, display a message on the interface.
console.log("User disconnected from their wallet. Please reconnect.");
}

Conclusion

Detecting disconnected users on MetaMask in your interface can be achieved by combining JavaScript events and web3 libraries. By implementing these solutions, you can ensure a seamless user experience while maintaining security and error handling. Remember to always check the Web3 library documentation for more information on event listeners and other features.