Ethers.js

ethers.js is a powerful JavaScript library for interacting with Ethereum and other EVM-compatible blockchain networks.

In this guide, we'll walk you through how to use ethers.js to interact with smart contracts on the Flow Blockchain.

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Installation

To use ethers.js in your project, you'll first need to install the package. To do this, run the following command:

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bashCopy code

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npm install --save ethers

Setup

After you install ethers.js, the next step is to import it into your project.

To do this, add the following line of code at the beginning of your JavaScript file:

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const ethers = require('ethers');

Connect to Flow

To connect to the Flow Blockchain with ethers.js, you need to create a new JsonRpcProvider instance with the appropriate RPC URL for Flow:

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const ethers = require('ethers');

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const url = 'https://testnet.evm.nodes.onflow.org/';

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const provider = new ethers.providers.JsonRpcProvider(url);

Note: If you want to connect to the Flow mainnet, replace the above URL with https://mainnet.evm.nodes.onflow.org.

Read data from the Blockchain

After you set up your provider, you can start reading data from the Flow Blockchain. For instance, to retrieve the latest block number, you can use the getBlockNumber method:

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async function getLatestBlock() {

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const latestBlock = await provider.getBlockNumber();

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console.log(latestBlock);

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}

Write data to the Blockchain

To send transactions or write data to the Flow Blockchain, you need to create a Signer. To do this, initialize a new Wallet object with your private key and the previously created Provider:

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const privateKey = 'YOUR_PRIVATE_KEY';

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const signer = new ethers.Wallet(privateKey, provider);

Note: Replace 'YOUR_PRIVATE_KEY' with the actual private key of the wallet you want to use.

Interact with smart contracts

ethers.js also allows interaction with smart contracts on the Flow Blockchain. To do this, create a Contract object using the Application Binary Interface (ABI) and the address of the deployed contract:

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const abi = [

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// ABI of deployed contract

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];

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const contractAddress = 'CONTRACT_ADDRESS';

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// read-only contract instance

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const contract = new ethers.Contract(contractAddress, abi, provider);

For contracts that require writing, you'll need to provide a Signer object instead of a Provider:

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// write-enabled contract instance

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const contract = new ethers.Contract(contractAddress, abi, signer);

Note: Replace 'CONTRACT_ADDRESS' with the actual address of your deployed contract.

After you set up your Contract object, you can call methods on the smart contract as needed:

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async function setValue(value) {

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const tx = await contract.set(value);

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console.log(tx.hash);

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}

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async function getValue() {

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const value = await contract.get();

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console.log(value.toString());

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}