Exploring Ethereum Account Balances In Javascript

Recently, Ethereum has been gaining in popularity among developers for its smart contract capabilities. As a result, it's important for developers to become familiar with Ethereum development and the various tools available. One such tool is the ability to interact with Ethereum accounts from within JavaScript.

In this blog post, we'll take a look at how you can use the web3.js library to obtain a user's Ethereum account balance from within a JavaScript application.

The web3.js library is an essential part of Ethereum development, as it provides the ability to interact with Ethereum nodes from within your application. By using web3.js, you'll be able to query Ethereum nodes for information, as well as send transactions.

To get started, we'll need to install web3.js. To do this, we can use either npm or yarn to install the library:

# To install with npm:
npm install web3

#To install with yarn:
yarn add web3

Once the web3.js library is installed, we can go ahead and import it into our application:

var Web3 = require('web3');

We'll then need to create an instance of web3.js for our application. This will provide us with the ability to interact with an Ethereum node:

var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'));

The next step is to obtain the address of the Ethereum account we want to query. To do this, we'll use the web3.eth.getAccounts() method, which will return an array of all the addresses associated with the Ethereum node we're connected to:

web3.eth.getAccounts(function (err, accounts) {
  // accounts is an array of addresses 
  var accountAddress = accounts[0];
});

Now that we have the address of the account we want to query, we can use the web3.eth.getBalance() method to retrieve the account balance. This method takes two parameters, the address of the account and a callback function:

web3.eth.getBalance(accountAddress, function(err, balance) {
  if (err) {
    console.error(err);
    return;
  }

  console.log(`Balance for account ${accountAddress}: ${balance} wei`);
});

The getBalance() method will return the account balance in wei, which is the lowest denomination of Ether. Assuming we want to display the balance in Ether, we'll need to convert the wei balance to Ether using the web3.utils.fromWei() method:

web3.eth.getBalance(accountAddress, function(err, balance) {
  if (err) {
    console.error(err);
    return;
  }

  var etherBalance = web3.utils.fromWei(balance, 'ether');

  console.log(`Balance for account ${accountAddress}: ${etherBalance} Ether`);
});

And that's it! This is all that's required to obtain an account balance from within a JavaScript application. With this simple code, you'll now be able to retrieve balances for any account on the Ethereum network.