Basic Hardhat Commands

Hardhat is a powerful tool for building decentralized applications (DApps) on the Ethereum blockchain, and one of the key features of the framework is its command-line interface (CLI). In this article, we’ll take a closer look at the basic Hardhat commands that you’ll use most frequently as a blockchain developer.

hardhat compile

The hardhat compile command is used to compile your Solidity contract files into JSON artifacts that can be deployed to the Ethereum blockchain. When you run this command, Hardhat will search for contract files in the directories specified in your configuration file (hardhat.config.js) and compile them using the Solidity compiler specified in the configuration.

To compile your contracts, you can run the following command:

hardhat compile

By default, this will compile all the contract files in your project. If you want to compile a specific contract, you can specify the contract name as an argument:

hardhat compile MyContract.sol

This will compile only the MyContract contract.

hardhat test

The hardhat test command is used to run your contract tests. When you run this command, Hardhat will search for test files in the directories specified in your configuration file and run them using the testing framework specified in the configuration.

To run your tests, you can use the following command:

hardhat test

By default, this will run all the tests in your project. If you want to run a specific test, you can specify the test file name as an argument:

hardhat test test/myTest.js

This will run only the myTest.js test file.

hardhat run

The hardhat run command is used to run custom tasks defined in your configuration file (hardhat.config.js). To run a custom task, you can use the following command:

hardhat run [taskName]

Replace [taskName] with the name of the task you want to run. For example, if you have a custom task named deploy, you can run it with the following command:

hardhat run deploy

Custom tasks are defined in the tasks object in the hardhat.config.js file. They can take arguments and access the Hardhat runtime environment. Here is an example of a custom task that prints the current network name:

module.exports = {
  tasks: {
    async printNetworkName(args, hardhatArguments) {
      console.log(await hardhatArguments.network.getNetworkName());
    },
  },
};

To run this task, you would use the following command:

hardhat run printNetworkName

hardhat debug

The hardhat debug command is used to start a debugger for your contract tests. When you run this command, Hardhat will start a debugger session, allowing you to step through your tests and inspect their behavior.

To start the debugger, you can use the following command:

hardhat debug

By default, this will start the debugger for all the tests in your project. If you want to debug a specific test, you can specify the test file name as an argument:

hardhat debug test/myTest.js

This will start the debugger for only the myTest.js test file.

Conclusion

These are just a few of the basic Hardhat commands that you’ll use as a blockchain developer. By mastering these commands, you’ll be able to compile, test, and debug your contracts, as well as run custom tasks to automate your workflow. With Hardhat, you’ll have all the tools you need to build powerful DApps on the Ethereum blockchain.

Exercises

To review these concepts, we will go through a series of exercises designed to test your understanding and apply what you have learned.

hardhat compile MyContract.sol

hardhat test test/myTest.js

hardhat run [taskName]

hardhat run deploy