Web3 by Example

Token(ERC-20) balance is stored in an ERC-20 standard smart contract. Learn more about smart contracts.

We use DAI token in goerli testnet as an example.

The ERC-20 Contract ABI, which is a common contract interface for tokens (this is the Human-Readable ABI format).

Set the provider that can be used to query the chain data.

Create the contract object. A contract object is an abstraction of a smart contract on the Ethereum Network. It allows for easy interaction with the smart contract.

Get the balance of an address. Format the DAI for displaying to the user

token-balance.js

const { ethers } = require("ethers");
(async () => {
  const daiAddress = "0xdc31Ee1784292379Fbb2964b3B9C4124D8F89C60";
  const daiAbi = [
    // Some details about the token
    "function name() view returns (string)",
    "function symbol() view returns (string)",
    // Get the account balance
    "function balanceOf(address) view returns (uint)",
    // Send some of your tokens to someone else
    "function transfer(address to, uint amount)",
    // An event triggered whenever anyone transfers to someone else
    "event Transfer(address indexed from, address indexed to, uint amount)",
  ];
  const provider = new ethers.providers.AlchemyProvider("goerli");
  const daiContract = new ethers.Contract(daiAddress, daiAbi, provider);
  const balance = await daiContract.balanceOf(
    "0x67CF3bF40b2b3b3D68F6c361AEf81F8AEb2dB637"
  );
  console.log(ethers.utils.formatUnits(balance, 18));
})();

output

❯ node token token-balance.js
113.908217455399736361