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Hardhat Tutorial

Step 1: Prepare directory and install Hardhat


Open a bash terminal session in the directory you will be saving your code to and do the following:

Create a new directory for your project:

mkdir sample-coin && cd sample-coin

Initiate your project:

yarn init --yes

Install project dependencies:

yarn add hardhat

Check hardhat installation:

yarn hardhat --version

Output:

2.18.3

Step 2: Initiate hardhat project

Initiate the hardhat project:

yarn hardhat init
  • On the first project choose Create a TypeScript project
  • Leave defaults for the rest of the prompts (press enter for all)

Open the sample-coin directory in VSCode:

code .

Explore files in default project with sample contract and tests


Step 3: Compile, test and deploy

Open a terminal session in VSCode, and ensure you are in the project directory (sample-coin)

Compile the sample project:

yarn hardhat compile

Note the artifacts directory. If you inspect the artifacts/contracts/Lock.json file you will see the resulting ABI (application binary interface) from the compiled contract which can be used for integration into your applications for interacting with the contract.


Run tests:

yarn hardhat test

Deploy (in-process blockchain testnet):

yarn hardhat run scripts/deploy.ts

Output:

Lock with 0.001ETH and unlock timestamp 1698225041 deployed to 0x5FbDB2315678afecb367f032d93F642f64180aa3

Step 4: Run standalone testnet, deploy smart contract, and interact with it using Hardhat console

Run the localhost testnet:

yarn hardhat node

In a new terminal session, deploy the smart contract to the localhost testnet:

yarn hardhat run scripts/deploy.ts --network localhost

Note the transaction details in the terminal running the hardhat localhost testnet

eth_sendTransaction
  Contract deployment: Lock
  Contract address:    0x5fbdb2315678afecb367f032d93f642f64180aa3
  Transaction:         0x5c0035470fb12ca9fac7b7aa74a1c511d447d3236aa88bb4a381ef824b30acc2
  From:                0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266
  Value:               0.001 ETH
  Gas used:            326112 of 30000000
  Block #1:            0x00e8e554ffe5311427114994c7aeb6ca6d148ea64aec59db516b51c9cbb25687

You will need the Contract address when interacting with the contract


NOTE: The Lock contract will lock the allocated ETH for 1 minute on deployment of the contract. A withdrawal will fail if you execute it within 1 minute of contract deployment.

Return to the terminal used to deploy the smart contract and start an instance of Hardhat console:

yarn hardhat console --network localhost

In the Hardhat console session, get the contract object using the contract address you got at deployment, and execute the contract withdraw() function:

const address = '0x5FbDB2315678afecb367f032d93F642f64180aa3';
const contract = await ethers.getContractAt("Lock", address);

//call withdraw
await contract.withdraw()

Output:

ContractTransactionResponse {
  provider: HardhatEthersProvider {
    _hardhatProvider: LazyInitializationProviderAdapter {
      _providerFactory: [AsyncFunction (anonymous)],
      _emitter: [EventEmitter],
      _initializingPromise: [Promise],
      provider: [BackwardsCompatibilityProviderAdapter]
    },
    _networkName: 'localhost',
    _blockListeners: [],
    _transactionHashListeners: Map(0) {},
    _eventListeners: []
  },
  blockNumber: 2,
  blockHash: '0x51284d053a28ad78adf18c297abc4b4e4536198df37bf02ad246cfdf4ee60e8f',
  index: undefined,
  hash: '0x4a1811e3c96fa406d451bd39730ae89f383ec645b12bd8855071120a97ac3993',
  type: 2,
  to: '0x5FbDB2315678afecb367f032d93F642f64180aa3',
  from: '0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266',
  nonce: 1,
  gasLimit: 30000000n,
  gasPrice: 768002900n,
  maxPriorityFeePerGas: 0n,
  maxFeePerGas: 972003670n,
  data: '0x3ccfd60b',
  value: 0n,
  chainId: 31337n,
  signature: Signature { r: "0x9adcdb381ca7819f6eb3325e0ef4999eb71465e06dab3157e88839ca2d1a388a", s: "0x3d28475451929f9c48fa0c917d2aee7aaa89b4f335cb84fcdc883285a10718e4", yParity: 0, networkV: null },
  accessList: []
}

To exit the hardhat console press Ctrl+C and then press Ctrl+C again.


Step 5: Modify contract to use console.log

In the contracts/Lock.sol smart contract, uncomment lines 5 and 25:

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

Compile and redeploy the smart contract and execute the withdraw() function again and note the console in the Hardhat node instance terminal:

console.log:
    Unlock time is '1698226099' and block timestamp is '1698226214'

Step 6: Clean up

To clean up the Hardhat project, kill any running nodes and run:

yarn hardhat clean

Next: ERC20 Token Tutorial

Home

Adapted from fangjun's Series: A Concise Hardhat Tutorial Series' Articles