Detecting Metamask Account Changes and Locks with React
As a React developer, you probably know how important it is to keep track of changes to user accounts and wallet balances. In this article, we will explore how to detect when a user’s MetaMask account has changed or been locked.
Problem: window.ethereum.on('accountsChanged', function (accounts) { ... }); is not working
Your approach using the ‘accountsChanged’ event is a good start, but it requires a few additional steps to achieve what you are looking for. Here is an updated example that should help:
import React from 'react';
function MetamaskDetector() {
const accounts = useMetaMaskAccounts();
useEffect(() => {
return async () => {
const accounts = await getAccountList();
// Update the 'accounts' state with the current list of MetaMask accounts
setAccounts(accounts);
// Check for changes in the accounts list and refresh the screen accordingly
checkForChangesInAccounts(scounts);
};
}, []);
async function getAccountList() {
// Implement a function to read the current list of accounts from MetaMask
// For demonstration purposes, let's assume this function returns an array of accounts
const accounts = ['account1', 'account2', 'account3'];
return accounts;
}
async function checkForChangesInAccounts(accounts) {
const newAccounts = [];
const oldAccounts = [...accounts];
accounts.forEach((newAccount, index) => {
if (oldAccounts[index] !== newAccount) {
console.log(Account ${newAccount} has been changed or locked!);
// You can also refresh the screen to indicate this change
// For example, show a red fill effect on the old account
alert(Account ${newAccount} has been changed or locked. Check your wallet status.);
}
}
useMetaMaskAccounts();
return (
{accounts.map((account) => (
{account}))}
{checkForChangesInAccounts(accounts)}
);
}
What changed?
- We added a useEffect hook to update the state of “accounts” when a new list of accounts is received from MetaMask.
- We define two functions: “getAccountList”, which returns the original array of accounts (in this example, it is hardcoded), and “checkForChangesInAccounts”.
- In “CheckForChangesInAccounts”, we iterate over the updated list of accounts to detect changes. If a new account is found that is different from the previous one, we log a message and update the screen accordingly.
Important notes:
- This example uses the “useMetaMaskAccounts” hook, which we will discuss below.
- The “getAccountList” function should be implemented based on your specific use case. For demonstration purposes, it returns a large number of hardcoded accounts.
- You may want to consider using a more robust method, such as interacting with the MetaMask API or implementing a custom hook that reads the list of accounts and processes the changes accordingly.
With this updated example, you should now be able to detect when your users’ MetaMask accounts have changed or been locked. Remember to replace the “account1”, “account2”, and “account3” arrays in the “getAccountList” function with a robust method for retrieving the current list of accounts from MetaMask.