How can I connect to Hedera Testnet using web3.js or ethers.js?

Question

I would like to interact with the Hedera Testnet using web3.js or ethers.js. How can I do this? I have previously interacted with Hedera Testnet using hedera-sdk-js, for example using the following code:

import {
    AccountBalanceQuery, 
    Client
} from "@hashgraph/sdk";

const client = new Client({
    network: "testnet"
});

const accountId = '0.0.3996280';
const balance = await new AccountBalanceQuery()
    .setAccountId(accountId)
    .execute(client);
    
console.log(
    `Balance of ${accountId} in Tinybars:`,
    balance.hbars.toTinybars().toString(10)
);

How can I do the equivalent of the above in web3.js/ ethers.js?

bguiz · Answer 1 · 2023-05-18T02:44:03.363

To connect using ethers.js

(1) First, obtain an RPC endpoint URL, which is detailed over at How can I connect to Hedera Testnet over RPC?. Once you have gotten that, substitute ${RPC_URL} in the code examples below with that value.

(2) Install ethers.js:

npm install ethers@v5

(3) Then use the following script to establish a connection to the RPC endpoint using ethers.providers.JsonRpcProvider, and query eth_blockNumber with it:

import { ethers } from 'ethers';

const web3Provider = new ethers.providers.JsonRpcProvider({
    url: '${RPC_URL}',
    headers: {
        'Access-Control-Allow-Origin': '*',
    },
});

async function main() {
    web3Provider.getBlockNumber()
        .then((blockNumber) => {
            console.log('block number', blockNumber);
        })
        .catch(console.error);

    web3Provider.getBalance(
        '0x00000000000000000000000000000000003cfa78')
        .then((balance) => {
            console.log('balance', balance.toBigInt());
        })
        .catch(console.error);
}

main();

score 2 · Answer 2 · answered May 10 '23 at 14:01

@bguiz answer should do it. There is also this tutorial that shows how you can do this with ethers.js along with a wallet like MetaMask.

https://youtu.be/mhqQToUEMBs?t=274

Here's a link to the code from the video, which is a function that you can reuse to connect a Hedera network (testnet/mainnet/previewnet) using Ethers. https://github.com/ed-marquez/hedera-example-metamask-counter-dapp/blob/master/src/components/hedera/walletConnect.js

The code is also shown below.

You start by creating a new ethers provider
Then defined the chainId of the network you want to connect to (testnet/mainnet/previewnet). If you're using a wallet like MetaMask, you can optionally switch to a Hedera network programatically, and then you can specify the JSON-RPC and network explorer URLs

Obtain the selected account

import { ethers } from "ethers";
 const network = "testnet";

 async function walletConnectFcn() {
     console.log(`\n=======================================`);

 // ETHERS PROVIDER
 const provider = new ethers.providers.Web3Provider(window.ethereum, "any");

 // SWITCH TO HEDERA TEST NETWORK
 console.log(`- Switching network to the Hedera ${network}...`);
 let chainId;
 if (network === "testnet") {
     chainId = "0x128";
 } else if (network === "previewnet") {
     chainId = "0x129";
 } else {
     chainId = "0x127";
 }

 await window.ethereum.request({
     method: "wallet_addEthereumChain",
     params: [
         {
             chainName: `Hedera ${network}`,
             chainId: chainId,
             nativeCurrency: { name: "HBAR", symbol: "ℏℏ", decimals: 18 },
             rpcUrls: [`https://${network}.hashio.io/api`],
             blockExplorerUrls: [`https://hashscan.io/${network}/`],
         },
     ],
 });
 console.log("- Switched ✅");

 // CONNECT TO ACCOUNT
 console.log("- Connecting wallet...");
 let selectedAccount;
 await provider
     .send("eth_requestAccounts", [])
     .then((accounts) => {
         selectedAccount = accounts[0];
         console.log(`- Selected account: ${selectedAccount} ✅`);
     })
     .catch((connectError) => {
         console.log(`- ${connectError.message.toString()}`);
         return;
     });

 return [selectedAccount, provider, network];

}

export default walletConnectFcn;

score 0 · Answer 3 · answered May 18 '23 at 02:45

To connect using web3.js

(1) First, obtain an RPC endpoint URL, which is detailed over at How can I connect to Hedera Testnet over RPC?. Once you have gotten that, substitute ${RPC_URL} in the code examples below with that value.

(2) Install web3.js:

npm install web3

(3) Then use the following script to establish a connection to the RPC endpoint using Web3.providers.HttpProvider, and query eth_blockNumber with it:

import Web3 from 'web3';

const web3Provider = new Web3(new Web3.providers.HttpProvider('${RPC_URL}'), {
    headers: [{
        name: 'Access-Control-Allow-Origin', value: '*'
    }],
    keepalive: true,
    withCredentials: false,
});

async function main() {
    web3Provider.eth.getBlockNumber()
        .then((blockNumber) => {
            console.log('block number', blockNumber);
        })
        .catch(console.error);

    web3Provider.eth.getBalance(
        '0x00000000000000000000000000000000003cfa78')
        .then((balance) => {
            console.log('balance', balance);
        })
        .catch(console.error);
}

main();

How can I connect to Hedera Testnet using web3.js or ethers.js?

3 Answers3

To connect using ethers.js

To connect using web3.js