Using Hardhat

What is Hardhat?

Hardhat is a development environment for Ethereum that helps developers manage and automate the common tasks involved in building smart contracts and decentralized applications. It can directly interact with Caldera's Ethereum API, allowing for the deployment of smart contracts into the Caldera network.

Additionally, Hardhat is a comprehensive set of tools for creating Ethereum-based software, which includes various components that aid in editing, compiling, debugging, and deploying smart contracts and decentralized applications. All of these components work together to create a complete development environment.

Creating a Hardhat Project

1. Create a directory for your project:

   mkdir hardhat && cd hardhat

2. Initialize the project, which will create a package.json file

   npm init -y

3. Install Hardhat

   npm install hardhat

4. Create a project

   npx hardhat

5. Create an empty hardhat.config.js and install the Ethers plugin to use the Ethers.js library to interact with the network.

   npm install @nomiclabs/hardhat-ethers ethers

Creating Your Smart Contract

1. Create a contracts directory

   mkdir contracts && cd contracts

2. Create your_contract.sol file in contracts directory

   touch your_contract.sol

Creating Your Configuration File

Modify the Hardhat configuration file and create a secure file to store your private key in.

1. Create a secrets.json file to store your private key

   touch secrets.json

2. Add your private key to secrets.json

   {
       "privateKey": "YOUR-PRIVATE-KEY-HERE"
   }

3. Add the file to your project's .gitignore, and never reveal your private key.

4. Modify the hardhat.config.js file

   • Import the Ethers.js plugin

   • Import the secrets.json file

   • Inside the module.exports add the Caldera network configuration

   require('@nomiclabs/hardhat-ethers');
   const { privateKey } = require('./secrets.json');
   
   module.exports = {
       solidity: "0.8.1",
       defaultNetwork: "rinkeby",
       networks: {
           xr: {
               url: "https://xr-sepolia-testnet.rpc.caldera.xyz/http",
               chainId: 2730,
           }
       },
   }

Deploying Your Smart Contract

1. Compile the contract

   npx hardhat compilejs

2. Create a new directory for the script and name it scripts and add a new file to it called deploy.js

   mkdir scripts && cd scriptstouch deploy.js

3. Create a deployment script, like the one below

   async function main() {
       // 1. Get the contract to deploy
       const Your_Contract = await ethers.getContractFactory('your_contract');
       console.log('Deploying Your_Contract...');
   
       // 2. Instantiating a new smart contract
       const your_contract = await Your_Contract.deploy();
   
       // 3. Waiting for the deployment to resolve
       await your_contract.deployed();
   
       // 4. Use the contract instance to get the contract address
       console.log('Your_Contract deployed to:', your_contract.address);
   }
   
   main()
   .then(() => process.exit(0))
   .catch((error) => {
       console.error(error);
       process.exit(1);
       }
   );

4. Deploy your_contract.sol using the command below

   npx hardhat run scripts/deploy.js --network xr