In this tutorial, you'll learn how to use Hardhat to compile, test, and deploy smart contracts. Before getting started, ensure that you have Node.js installed on your local machine, along with a code editor like VSCode. To have a better performance, we also use pnpm for package management. However, a faster alternative like bun is also welcome.

Note: If you are on Windows, you may want to use WSL or Git Bash to run the commands.

Create a new folder
bash mkdir hardhat-tutorial

Change dir to hardhat-tutorial
cd hardhat-tutorial

Initialize a new Node.js project with a package.json file in it

pnpm init

package.json file is the entry point for the project. It contains the project's metadata and dependencies. And any folder contains a package.json file is considered a Node.js project.

In package.json file, you will see the following content:

name: The name of the project.

scripts: A set of scripts that can be run using pnpm run {script - name}

In your termainal, run the following command to install Hardhat

pnpm add @nomicfoundation/hardhat-toolbox hardhat @nomicfoundation/hardhat-chai-matchers
@nomicfoundation/hardhat-ethers @nomicfoundation/hardhat-ignition @openzeppelin/contracts dayjs dotenv ethers
solidity-coverage chai@4.4.1 @types/chai

After the installation, you will see a node_modules folder in your project. Please add this folder to your .gitignore file. Do not commit this folder to your repository.

And now you will see the following content added to your package.json file's dependencies field

Add test, coverage and compile scripts to your package.json file.

test: Run tests
coverage: Run tests with coverage
compile: Compile contracts

Create a new file named hardhat.config.ts in the root of your project. This file is the configuration file for Hardhat.

Add the following code to the hardhat.config.ts file

dotenv is use for loading the private key into the system. You can check this link to know how to export your private key from Metamask. DO NOT put your private key in your code and commit it to the repository!!!!

Create a .env file in the root of your project and add the following content

Put your private key in the .env file

Create a file called tsconfig.json in the root of your project

The tsconfig.json file is the configuration file for TypeScript. Typescript is a superset of JavaScript that adds static typing to the language. It is used to compile the TypeScript code to JavaScript.

Add the following content to the tsconfig.json file

Create a folder named contracts in the root of your project and create a file named HelloWorld.sol in it.

Add the following content to the HelloWorld.sol file

Run the following command to compile the contract

pnpm run compile

Now you have successfully set up a Hardhat project. Next, we will test the contract.

Testing is an essential part of the development process. It helps to ensure that the code works as expected.

Create a folder named test in the root of your project and create a file named HelloWorld.spec.ts in it.

Add a describe block to the HelloWorld.spec.ts file

A describe block organizes related tests under a common description, making it easier to understand the specific functionality or behavior being tested. This structure is particularly useful for grouping tests that share similar purposes or behaviors.

Add a deploy function to the HelloWorld.spec.ts file

The deploy function is used to deploy the contract to the network. The contract will be deployed to the hardhat testing network, so you don't need to worry about the gas fee.

Note, this HelloWorld is the same as the contract name in the HelloWorld.sol file.

Add a test function to the HelloWorld.spec.ts file

The test function is used to test the contract. It checks if the contract works as expected.

Note, this helloWorld is the same as the contract's function name in the HelloWorld.sol file.

You can simply expect some results from the contract and check if the results are correct.

You can run the test by running the following command

pnpm run test

Congratulations!

You have successfully set up a Hardhat project. In the next section, you will learn how to connect your sma rt contract with the frontend.