Deploy a Smart Contract Using Hardhat

Pre-requisites​

• Node.js Stable Version
• Git

Create the Project​

Let's start by creating a new node project:

mkdir projectname
cd projectname

Initiate npm:

npm init -y

Install hardhat:

npm install --save-dev hardhat

Now, let's create a new hardhat project. Run in your project root:

npx hardhat

You should see the following prompt:

Choose the JavaScript project and go through these steps to compile, test and deploy the sample contract.

Your hardhat project should look like something this:

.
├── README.md
├── contracts
│ └── Lock.sol
├── hardhat.config.js
├── package-lock.json
├── package.json
├── scripts
│ └── deploy.js
└── test
└── Lock.js

Check the Contract​

The contracts folder contains Lock.sol, which is a sample contract which consistis of a simple digital lock, where users could only withdraw funds after a given period of time.

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.9;

// Uncomment this line to use console.log
// import "hardhat/console.sol";

contract Lock {
    uint public unlockTime;
    address payable public owner;

    event Withdrawal(uint amount, uint when);

    constructor(uint _unlockTime) payable {
        require(
            block.timestamp < _unlockTime,
            "Unlock time should be in the future"
        );

        unlockTime = _unlockTime;
        owner = payable(msg.sender);
    }

    function withdraw() public {
        // Uncomment this line, and the import of "hardhat/console.sol", to print a log in your terminal
        // console.log("Unlock time is %o and block timestamp is %o", unlockTime, block.timestamp);

        require(block.timestamp >= unlockTime, "You can't withdraw yet");
        require(msg.sender == owner, "You aren't the owner");

        emit Withdrawal(address(this).balance, block.timestamp);

        owner.transfer(address(this).balance);
    }
}

The above is an auto-generated smart contract by hardhat. You can replace it with your own smart contract. If you want to understand what the smart contract does, it's a Lock contract, which will lock funds for a specific time period and allows withdrawals only past that point. Some important things to note are data types. event means that we can subscribe to it like a webhook and wait for a ping to the client side whenever a withdrawal is triggered with emit from inside the function withdraw().

Set Up the Contract​

1. Go to hardhat.config.js
2. Update the hardhat-config with shimmer network details as shown below:

module.exports = {
  solidity: '0.8.18',
  defaultNetwork: 'shimmerevm',
  networks: {
    shimmerevm: {
      url: 'https://json-rpc.evm.shimmer.network',
      chainId: 148,
      timeout: 60000,
    },
  },
};

1. Create a .env file in the project root to store your network id and jsonrpc if you want to keep it private. You can then refer to them by process.env.SHIMMEREVM_TESTNET_JSONRPC.

Compile the Contract​

To compile the contract, you first need to install the Hardhat Toolbox package:

npm install --save-dev @nomicfoundation/hardhat-toolbox

Then, simply run to compile:

npx hardhat compile

Deploy Your Contract on ShimmerEVM​

Run this command in root of the project directory:

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

The contract will be deployed on ShimmerEVM, and you can check the deployment status here on the explorer.

If you want to further verify your contract, add the following to your hardhat.config.js:

etherscan: {
    apiKey:
      {
        shimmerevm: "xxx"
      },
    customChains: [
      {
        apikey: "xxx",
        network: "shimmerevm",
        chainId: 148,
        urls: {
          apiURL: "https://explorer.evm.shimmer.network/api",
          browserURL: "https://explorer.evm.shimmer.network/"
        }
      }
    ]
  },

Then you can verify by running:

npx hardhat verify --network shimmerevm <address> <unlock time>

And Voila! You've successfully deployed your first Hardhat Smart Contract on ShimmerEVM and verified it on explorer.