Hardhat: Deploying a Smart Contract

Learn how to deploy a simple Solidity-based smart contract to Evmos using the Hardhat environment

Hardhat (opens new window) is a flexible development environment for building Ethereum-based smart contracts. It is designed with integrations and extensibility in mind

Install Dependencies

Before proceeding, you need to install Node.js (we'll use v16.x) and the npm package manager. You can download directly from Node.js (opens new window) or in your terminal:

Copy curl -sL https://deb.nodesource.com/setup_16.x | sudo -E bash - sudo apt install -y nodejs

Copy # You can use homebrew (https://docs.brew.sh/Installation) $ brew install node # Or you can use nvm (https://github.com/nvm-sh/nvm) $ nvm install node

You can verify that everything is installed correctly by querying the version for each package:

Copy $ node -v ... $ npm -v ...

Create Hardhat Project

To create a new project, navigate to your project directory and run:

Copy $ npx hardhat 888 888 888 888 888 888 888 888 888 888 888 888 888 888 888 8888888888 8888b. 888d888 .d88888 88888b. 8888b. 888888 888 888 "88b 888P" d88" 888 888 "88b "88b 888 888 888 .d888888 888 888 888 888 888 .d888888 888 888 888 888 888 888 Y88b 888 888 888 888 888 Y88b. 888 888 "Y888888 888 "Y88888 888 888 "Y888888 "Y888 👷 Welcome to Hardhat v2.9.3 👷‍ ? What do you want to do? … Create a basic sample project ❯ Create an advanced sample project Create an advanced sample project that uses TypeScript Create an empty hardhat.config.js Quit

Following the prompts should create a new project structure in your directory. Consult the Hardhat config page (opens new window) for a list of configuration options to specify in hardhat.config.js. Most importantly, you should set the defaultNetwork entry to point to your desired JSON-RPC network:

Copy module.exports = { defaultNetwork: "local", networks: { hardhat: { }, local: { url: "http://localhost:8545/", accounts: [privateKey1, privateKey2, ...] } }, ... }

Copy module.exports = { defaultNetwork: "testnet", networks: { hardhat: { }, testnet: { url: "https://eth.bd.evmos.dev:8545", accounts: [privateKey1, privateKey2, ...] } }, ... }

To ensure you are targeting the correct network, you can query for a list of accounts available to you from your default network provider:

Copy $ npx hardhat accounts 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266 0x70997970C51812dc3A010C7d01b50e0d17dc79C8 0x3C44CdDdB6a900fa2b585dd299e03d12FA4293BC 0x90F79bf6EB2c4f870365E785982E1f101E93b906 ...

Deploying a Smart Contract

You will see that a default smart contract, written in Solidity, has already been provided under contracts/Greeter.sol:

Copy pragma solidity ^0.8.0; import "hardhat/console.sol"; contract Greeter { string private greeting; constructor(string memory _greeting) { console.log("Deploying a Greeter with greeting:", _greeting); greeting = _greeting; } function greet() public view returns (string memory) { return greeting; } function setGreeting(string memory _greeting) public { console.log("Changing greeting from '%s' to '%s'", greeting, _greeting); greeting = _greeting; } }

This contract allows you to set and query a string greeting. Hardhat also provides a script to deploy smart contracts to a target network; this can be invoked via the following command, targeting your default network:

Copy npx hardhat run scripts/deploy.js

Hardhat also lets you manually specify a target network via the --network <your-network> flag:

Copy npx hardhat run --network {{ $themeConfig.project.rpc_url_local }} scripts/deploy.js

Copy npx hardhat run --network {{ $themeConfig.project.rpc_url_testnet }} scripts/deploy.js

Finally, try running a Hardhat test:

Copy $ npx hardhat test Compiling 1 file with 0.8.4 Compilation finished successfully Greeter Deploying a Greeter with greeting: Hello, world! Changing greeting from 'Hello, world!' to 'Hola, mundo!' ✓ Should return the new greeting once it's changed (803ms) 1 passing (805ms)