เริ่มต้นเขียน Solidity ด้วย Hardhat

mkdir hello-solidity
cd hello-sollidity

npm init -y
# หรือ yarn
yarn init -y

npm install hardhat --save-dev
# Yarn
yarn add hardhat -D

npx hardhat

# yarn
yarn hardhat

yarn hardhat

yarn run v1.22.18
$ /Users/chai/dev/hello-solidity/node_modules/.bin/hardhat
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888    888                      888 888               888
888    888                      888 888               888
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888    888     "88b 888P"  d88" 888 888 "88b     "88b 888
888    888 .d888888 888    888  888 888  888 .d888888 888
888    888 888  888 888    Y88b 888 888  888 888  888 Y88b.
888    888 "Y888888 888     "Y88888 888  888 "Y888888  "Y888

👷 Welcome to Hardhat v2.9.2 👷‍

✔ What do you want to do? · Create a basic sample project
✔ Hardhat project root: · /Users/chai/dev/hello-solidity
✔ Do you want to add a .gitignore? (Y/n) · y
✔ Do you want to install this sample project's dependencies with yarn (@nomiclabs/hardhat-waffle ethereum-waffle chai @nomiclabs/hardhat-ethers ethers)? (Y/n) · y
...
...

✨ Project created ✨
See the README.md file for some example tasks you can run.
✨  Done in 48.59s.

tree -L 2 -I node_modules

├── README.md
├── contracts
│   └── Greeter.sol
├── hardhat.config.js
├── package.json
├── scripts
│   └── sample-script.js
├── test
│   └── sample-test.js
└── yarn.lock

//SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

import "hardhat/console.sol";

contract Greeter {
    string private greeting;

    constructor(string memory _greeting) {
        console.log("Deploying a Greeter with greeting:", _greeting);
        greeting = _greeting;
    }

    function greet() public view returns (string memory) {
        return greeting;
    }

    function setGreeting(string memory _greeting) public {
        console.log("Changing greeting from '%s' to '%s'", greeting, _greeting);
        greeting = _greeting;
    }
}

//SPDX-License-Identifier: Unlicense

pragma solidity ^0.8.0;

contract Greeter {

}

constructor(string memory _greeting) {
    console.log("Deploying a Greeter with greeting:", _greeting);
    greeting = _greeting;
}

import "hardhat/console.sol";
console.log("");

function greet() public view returns (string memory) {
    return greeting;
}

function setGreeting(string memory _greeting) public {
    console.log("Changing greeting from '%s' to '%s'", greeting, _greeting);
    greeting = _greeting;
}

string private greeting;

const hre = require("hardhat");

async function main() {
  // Hardhat always runs the compile task when running scripts with its command
  // line interface.
  //
  // If this script is run directly using `node` you may want to call compile
  // manually to make sure everything is compiled
  // await hre.run('compile');

  // We get the contract to deploy
  const Greeter = await hre.ethers.getContractFactory("Greeter");
  const greeter = await Greeter.deploy("Hello, Hardhat!");

  await greeter.deployed();

  console.log("Greeter deployed to:", greeter.address);
}

npx hardhat compile

├── artifacts
│   ├── build-info
│   ├── contracts
│   └── hardhat

//1. บรรทัดนี้ เป็นคำสั่งเพื่อสร้าง contract factory จาก contract ที่ชื่อ `Greeter`
const Greeter = await hre.ethers.getContractFactory('Greeter');

// 2. เมื่อได้ factory ก็ใช้คำสั่ง deploy จะเห็นว่า "Hello, Hardhat!" คือค่า argument ที่ถูกส่งไปใน contructor นั่นเอง
const greeter = await Greeter.deploy('Hello, Hardhat!');

// 3. เรียก `deployed()` เพื่อรอ transaction confirm เพราะข้อมูลที่ deploy มันคือการเซฟลง blockchain
await greeter.deployed();

npx hardhat run scripts/sample-scripts.js

Deploying a Greeter with greeting: Hello, Hardhat!
Greeter deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3

const Greeter = await hre.ethers.getContractFactory('Greeter');
const greeter = await Greeter.deploy('Hello, Hardhat!');

await greeter.deployed();

const greet = await greeter.greet();
console.log('greeting : ', greet);

Deploying a Greeter with greeting: Hello, Hardhat!
Greeter deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3
greeting :  Hello, Hardhat!

const Greeter = await hre.ethers.getContractFactory('Greeter');
const greeter = await Greeter.deploy('Hello, Hardhat!');

await greeter.deployed();

console.log('Greeter deployed to:', greeter.address);

const greet = await greeter.greet();
console.log('greeting : ', greet);

const tx = await greeter.setGreeting('This is new greeting.');
tx.wait();

const newGreet = await greeter.greet();
console.log('greeting (new) : ', newGreet);

Deploying a Greeter with greeting: Hello, Hardhat!
Greeter deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3
greeting :  Hello, Hardhat!
Changing greeting from 'Hello, Hardhat!' to 'This is new greeting.'
greeting (new) :  This is new greeting.