#Using Ethers

Hardhat Ignition provides a variant based on using Ethers as your connection library. Ethers is an alternative to Viem for interacting with the Ethereum Blockchain and its ecosystem.

The Ethers support in Hardhat Ignition includes a helper function, for use in Hardhat tests and scripts, that allows you to deploy Ignition modules and get back the deployed contracts as Ethers.js contract instances.

#Installation

To install Hardhat Ignition with Ethers support in an existing Hardhat project, you will need:

• Hardhat version 3.0.0 or higher
• Ethers version 6.14.0 or higher

You can also follow Hardhat's Quick Start guide and pick the option for Ethers and Mocha during initialization to create a new Hardhat Ethers project from scratch.

From the root directory of your Hardhat project run:

npm install --save-dev @nomicfoundation/hardhat-ignition-ethers

pnpm add -D @nomicfoundation/hardhat-ignition-ethers ethers

Then enable the plugin in your config file:

import HardhatIgnitionEthersPlugin '@nomicfoundation/hardhat-ignition-ethers'

export default {
  plugins: [
    HardhatIgnitionEthersPlugin,
  ],
  // ... rest of your config
}

#The Ignition object

The @nomicfoundation/hardhat-plugin-ethers plugin adds an ignition object to each NetworkConnection created by Hardhat.

The ignition object exposes a deploy method, which takes an Ignition module, deploys it against the current network, like Hardhat Network, and returns the results of the module as Ethers.js contract instances.

The deploy method takes the Module as its first argument:

import { buildModule } from "@nomicfoundation/hardhat-ignition/modules";
import hre from "hardhat";

const ApolloModule = buildModule("Apollo", (m) => {
  const apollo = m.contract("Rocket", ["Saturn V"]);

  return { apollo };
});

it("should have named the rocket Saturn V", async function () {
  const connection = await hre.network.connect();
  const { apollo } = await connection.ignition.deploy(ApolloModule);

  assert.equal(await apollo.getFunction("name")(), "Saturn V");
});

The ignition.deploy method returns an object with an Ethers contract instance per Future returned as a result in the module.

#Sending transactions with a different account

The ignition.deploy method will default to using the first account in the accounts array of the Hardhat NetworkConnection as the sender for all transactions.

You can change this by passing a defaultSender within the options object as a second argument to the deploy method:

const connection = await hre.network.connect();
const [first, second] = await connection.ethers.getSigners();

const result = await connection.ignition.deploy(ApolloModule, {
  defaultSender: second.address,
});