Metamask: Listening to metamask events using broadcasts in an Angular application
Listening to Metamask events using ether in an Angular app
When you’re building your Angular application that connects to different blockchain accounts via MetaMask, it’s crucial to be informed about the events that happen in the context of your Ethereum-based services. In this article, we’ll explore how to set up metamask event listeners using ethereum and angular.
What are metamask events?
MetaMask events are messages that can be sent or received from the MetaMask platform that indicate various changes in the status of your Ethereum account. These events can include things like:
- New accounts created
- Wallet balance updated
- Transaction events (e.g. transaction confirmation)
- Account ownership changes
Ethers Provider and Signer Setup
To listen to metamask events in your Angular application, you will first need to obtain an instance of the ethers provider. This will allow you to interact with the MetaMask API and send and receive events.
import { Component, OnInit } from '@angular/core';
import * as ethers from 'ethers';
@Component({
selector: 'example application',
template: '
component example.
'
})
export class ExampleComponent implements OnInit {
myProvider: ethers.providers.Provider;
constructor () { }
ngOnInit(): void {
this.myProvider = new ethers.providers.Web3Provider(window.ethereum);
}
}
In the code above, we create an instance of a Web3 provider using the “ethers” package. You can obtain a Web3Provider instance by logging into your MetaMask account and then accessing the provider instance.
Listening to events
To listen to metamask events, you will need to subscribe to certain types of events using the ether subscription API.
import { Subscription } from 'rxjs';
const subscription: Subscription = this.myProvider.eventSubscriptions.subscribe((event) => {
console.log(Event received: ${event.name}
); });
In the above code, we create a subscription that listens to events. We can specify the event types by passing them as arguments to the `subscribe'' method.
Angular Service
To make it easier to manage subscriptions and listen to events in your Angular application, you can create a service.
Event received: ${event.name}
import { Injectable } from '@angular/core';
import { EventSubscription } from './event-subscription';
@Injectable({
Sent by: 'root'
})
export class MetamaskService {
private subscription : Subscription;
constructor () { }
connectAccount(account: string): void {
this.subscription = this.myProvider.eventSubscriptions.subscribe((event) => {
console.log(
);
});
// Log out when the account is closed
window.ethereum.onDisconnect(() => {
this.subscription.unsubscribe();
});
}
}
In the code above, we have created a MetamaskService class that manages subscriptions and listens for events. We may use samples from this service to log into your MetaMask account.
All things considered
To listen to metamask events in your Angular application you will need:
- Create an ether provider instance.
- Subscribe to certain types of events using the "subscribe" method.
- Use the service to manage subscriptions and manage event listeners.
Here is an updated example that shows how to use these concepts:
“ typewriter
import { Component, OnInit } from ‘@angular/core’;
import * as ethers from ‘ethers’;
@Component({
selector: ‘example-app’,
template : ‘
example component.
‘
})
Export class ExampleComponent implements OnInit {
myProvider: ethers.providers.Web3Provider;
subscription: Subscription;
constructor () { }
ngOnInit(): void {
this.myProvider = new ethers .providers.Web3Provider(window.