Instalasi Hardhat 3 - Professional Development Setup

Panduan lengkap setup Hardhat 3 (versi terbaru 2025) untuk pengembangan smart contract secara profesional.

---

Mengapa Menggunakan Hardhat?

Remix bagus untuk belajar, tapi Hardhat lebih baik untuk:

• ✅ Menulis automated tests
• ✅ Deploy ke multiple networks
• ✅ Bekerja dalam tim
• ✅ Version control (Git)
• ✅ Professional workflows
• ✅ TypeScript support
• ✅ Modern tooling

---

Prerequisites (Yang Dibutuhkan)

1. Install Node.js

Minimum Version: Node.js 22 atau lebih tinggi

Check versi Node.js Anda:

node --version
# Harus menampilkan v22.0.0 atau lebih tinggi

npm --version
# Harus menampilkan 7.0.0 atau lebih tinggi

Belum punya Node.js?

1. Download dari https://nodejs.org
2. Pilih versi LTS (Long Term Support)
3. Install sesuai sistem operasi Anda
4. Restart terminal setelah instalasi

2. Install Code Editor

Rekomendasi: Visual Studio Code

1. Download dari https://code.visualstudio.com
2. Install extensions yang berguna:
   • Solidity (by Juan Blanco)
   • Hardhat Solidity (by Nomic Foundation)
   • ESLint
   • Prettier

---

Setup Hardhat 3 Project

Step 1: Buat Folder Project

1. Buat folder baru:

mkdir my-hardhat-project
cd my-hardhat-project

Penjelasan:

• mkdir = membuat folder baru (make directory)
• cd = masuk ke dalam folder (change directory)

2. Initialize npm project:

npm init -y

Penjelasan:

• npm init = membuat file package.json (konfigurasi project)
• -y = menjawab "yes" untuk semua pertanyaan secara otomatis

Hasil: File package.json terbuat di folder project Anda

---

Step 2: Install Hardhat

Install Hardhat sebagai development dependency:

npm install --save-dev hardhat

Penjelasan:

• npm install = mengunduh dan menginstall package
• --save-dev = menyimpan sebagai development dependency
• Proses ini memakan waktu ~30 detik

Tunggu sampai muncul:

added 1 package, and audited 2 packages in 5s

---

Step 3: Initialize Hardhat Project

1. Jalankan Hardhat initialization wizard:

npx hardhat --init

Penjelasan:

• npx = menjalankan package yang sudah diinstall
• hardhat --init = memulai wizard setup Hardhat 3

Perhatikan Flag --init

Gunakan --init (dengan dua dash), BUKAN init. Jika Anda menjalankan npx hardhat init akan muncul error HHE3: No Hardhat config file found.

2. Hardhat 3 Wizard akan muncul:

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👷 Welcome to Hardhat v3.1.12 👷

✔ Which version of Hardhat would you like to use? · hardhat-3
✔ Where would you like to initialize the project? · .
✔ What type of project would you like to initialize? · node-test-runner-viem
✔ Hardhat only supports ESM projects. Would you like to change "./package.json" to turn your project into ESM? (Y/n) · true

3. Pilih opsi berikut:

Pertanyaan	Pilihan	Penjelasan
Hardhat version?	hardhat-3	Versi terbaru
Initialize path?	. (Enter)	Gunakan folder saat ini
Project type?	node-test-runner-viem	Modern stack dengan Viem
Turn into ESM?	Y (Yes)	ECMAScript Modules (modern JS)
Install dependencies?	Y (Yes)	Install semua package yang dibutuhkan

Penjelasan:

• hardhat-3: Versi terbaru dengan fitur modern
• ESM: ECMAScript Modules adalah JavaScript standard modern
• node-test-runner-viem: Menggunakan Node.js test runner + Viem library
• Viem: Library modern yang lebih cepat dari ethers.js

4. Instalasi dependencies:

✨ Template files copied ✨

npm install --save-dev "@nomicfoundation/hardhat-toolbox-viem@^5.0.3" ...

added 111 packages, and audited 198 packages in 53s
✨ Dependencies installed ✨

Proses ini:

• Menginstall ~111 packages
• Memakan waktu 1-2 menit
• Ini normal, jangan khawatir!

5. Selesai! Anda akan melihat:

Give Hardhat a star on Github if you're enjoying it! ⭐️✨
https://github.com/NomicFoundation/hardhat

---

Step 4: Struktur Project

Setelah setup, folder project Anda akan terlihat seperti ini:

my-hardhat-project/
├── contracts/              # Smart contracts Anda
│   └── Counter.sol        # Sample contract (bisa dihapus)
│   └── Counter.t.sol      # Sample Solidity test (bisa dihapus)
├── ignition/              # Deployment scripts
│   └── modules/
│       └── Counter.ts     # Sample deployment (bisa dihapus)
├── test/                  # Test files (TypeScript)
│   └── Counter.ts         # Sample test (bisa dihapus)
├── scripts/               # Custom scripts
│   └── send-op-tx.ts      # Sample script
├── node_modules/          # Installed packages (jangan diubah!)
├── hardhat.config.ts      # Konfigurasi utama Hardhat
├── package.json           # Project dependencies
├── tsconfig.json          # TypeScript configuration
└── .gitignore            # Git ignore file

Penjelasan setiap folder:

Folder/File	Fungsi
contracts/	Tempat menulis smart contracts (.sol)
Counter.sol	Sample contract dengan fitur Hardhat 3
Counter.t.sol	Solidity test (gaya Foundry, baru di Hardhat 3!)
ignition/modules/	Deployment scripts menggunakan Hardhat Ignition
test/	Test files dalam TypeScript/JavaScript
scripts/	Custom automation scripts
hardhat.config.ts	Konfigurasi network, compiler, plugins
node_modules/	Package yang diinstall (diabaikan oleh Git)

Note: Hardhat 3 mendukung Solidity tests (.t.sol) DAN TypeScript tests!

---

Step 5: Bersihkan Sample Files

Hapus file-file sample yang tidak diperlukan:

# Hapus sample contracts
rm contracts/Counter.sol
rm contracts/Counter.t.sol

# Hapus sample deployment
rm ignition/modules/Counter.ts

# Hapus sample test
rm test/Counter.ts

Opsional: Anda bisa menyimpan file-file ini untuk dipelajari nanti.

---

Konfigurasi untuk Testnet

Step 6: Install Dependencies Tambahan

1. Install dotenv untuk environment variables:

npm install --save-dev dotenv

Penjelasan:

• dotenv = memuat secret keys dari file .env
• Menjaga private key tetap aman (tidak di-commit ke Git)

2. Install Hardhat Ethers (opsional, untuk compatibility):

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

---

Step 7: Setup Environment Variables

1. Buat file .env:

# Di Windows:
type nul > .env

# Di Mac/Linux:
touch .env

2. Tambahkan private key ke .env:

Buka file .env dan tambahkan:

PRIVATE_KEY=your_private_key_here_without_0x
ETHERSCAN_API_KEY=your_etherscan_api_key_here

Cara mendapatkan Etherscan API Key (untuk verify contract - GRATIS):

1. Buka https://etherscan.io dan buat akun (gratis)
2. Login → Klik username → "API Keys"
3. Klik "Add" → Beri nama (contoh: "hardhat")
4. Copy API Key Token
5. Paste ke file .env

Cara mendapatkan private key dari MetaMask:

1. Buka MetaMask extension
2. Klik 3 titik (⋮) → Account Details
3. Klik "Show private key"
4. Masukkan password MetaMask
5. Copy private key
6. Paste ke file .env (tanpa "0x" di awal)

⚠️ SANGAT PENTING:

• ❌ JANGAN PERNAH share private key Anda!
• ❌ JANGAN commit .env ke Git!
• ✅ File .gitignore sudah melindunginya
• ✅ Gunakan testnet wallet, bukan wallet utama

---

Step 8: Konfigurasi Hardhat untuk Testnet

Edit file hardhat.config.ts:

Ganti semua isi file dengan konfigurasi di bawah ini:

import { HardhatUserConfig } from "hardhat/config";
import hardhatToolboxViemPlugin from "@nomicfoundation/hardhat-toolbox-viem";
import hardhatIgnitionViemPlugin from "@nomicfoundation/hardhat-ignition-viem";
import hardhatVerify from "@nomicfoundation/hardhat-verify";
import * as dotenv from "dotenv";

// Load environment variables
dotenv.config();

const config: HardhatUserConfig = {
  // Register Hardhat 3 plugins
  plugins: [
    hardhatToolboxViemPlugin,
    hardhatIgnitionViemPlugin,
    hardhatVerify,
  ],

  // Solidity compiler configuration
  solidity: {
    version: "0.8.30",
    settings: {
      optimizer: {
        enabled: true,
        runs: 200,
      },
    },
  },

  // Network configurations
  networks: {
    // Sepolia Testnet
    sepolia: {
      type: "http",
      url: "https://ethereum-sepolia-rpc.publicnode.com",
      accounts: process.env.PRIVATE_KEY ? [`0x${process.env.PRIVATE_KEY}`] : [],
      chainId: 11155111,
    },
  },

  // Chain descriptors untuk block explorer
  chainDescriptors: {
    // Ethereum Sepolia
    11155111: {
      name: "Sepolia",
      blockExplorers: {
        etherscan: {
          name: "Etherscan",
          url: "https://sepolia.etherscan.io",
          apiUrl: "https://api-sepolia.etherscan.io/api",
        },
      },
    },
  },

  // Verification settings
  verify: {
    etherscan: {
      apiKey: process.env.ETHERSCAN_API_KEY || "",
    },
  },

  // File paths
  paths: {
    sources: "./contracts",
    tests: "./test",
    cache: "./cache",
    artifacts: "./artifacts",
  },
};

export default config;

Penjelasan konfigurasi:

Setting	Penjelasan
plugins	Plugin Hardhat 3 yang digunakan
hardhatToolboxViemPlugin	Toolbox dengan Viem library
hardhatIgnitionViemPlugin	Deployment system Hardhat 3
hardhatVerify	Plugin untuk verify contract di block explorer
solidity.version	Versi compiler Solidity
optimizer.enabled	Optimasi bytecode untuk hemat gas
type: "http"	Tipe network (wajib di Hardhat 3)
networks.sepolia	Konfigurasi Sepolia testnet
chainId: 11155111	Chain ID untuk Sepolia testnet
chainDescriptors	Informasi block explorer untuk Etherscan
verify.etherscan.apiKey	API key untuk verify contract di Etherscan

---

Deploy CrowdFund Challenge dengan Hardhat

Sekarang kita akan deploy CrowdFund contract dari Final Challenge Sesi 1 menggunakan Hardhat 3. Ini adalah cara professional untuk deploy smart contract yang sudah Anda buat di Remix!

Step 9: Buat Smart Contract CrowdFund

1. Buat file contracts/CrowdFund.sol:

# Di Windows:
type nul > contracts/CrowdFund.sol

# Di Mac/Linux:
touch contracts/CrowdFund.sol

2. Isi dengan kode smart contract CrowdFund:

Buka contracts/CrowdFund.sol di VS Code dan tulis implementasi lengkap dari challenge Sesi 1:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.30;

/// @title CrowdFund - Decentralized Crowdfunding Platform
/// @notice Platform crowdfunding terdesentralisasi di Ethereum
/// @dev Challenge Final Ethereum Co-Learning Camp

contract CrowdFund {
    // ============================================
    // ENUMS & STRUCTS
    // ============================================

    enum CampaignStatus {
        Active,     // 0: Sedang berjalan, menerima kontribusi
        Successful, // 1: Target tercapai, dana bisa di-claim
        Failed,     // 2: Deadline lewat, target tidak tercapai
        Claimed     // 3: Dana sudah di-claim oleh creator
    }

    struct Campaign {
        uint256 campaignId;
        address creator;
        string title;
        string description;
        uint256 goalAmount;
        uint256 currentAmount;
        uint256 deadline;
        uint256 createdAt;
        CampaignStatus status;
        uint256 contributorCount;
    }

    // ============================================
    // STATE VARIABLES
    // ============================================

    uint256 public campaignCounter;
    uint256 public constant MIN_GOAL = 0.01 ether;
    uint256 public constant MAX_DURATION = 90 days;
    uint256 public constant MIN_DURATION = 1 days;
    uint256 public constant MIN_CONTRIBUTION = 0.001 ether;

    mapping(uint256 => Campaign) public campaigns;
    mapping(uint256 => mapping(address => uint256)) public contributions;
    mapping(uint256 => mapping(address => bool)) public hasContributed;
    mapping(address => uint256[]) public creatorCampaigns;

    // ============================================
    // EVENTS
    // ============================================

    event CampaignCreated(uint256 indexed campaignId, address indexed creator, string title, uint256 goalAmount, uint256 deadline);
    event ContributionMade(uint256 indexed campaignId, address indexed contributor, uint256 amount, uint256 totalRaised);
    event CampaignSuccessful(uint256 indexed campaignId, uint256 totalRaised);
    event FundsClaimed(uint256 indexed campaignId, address indexed creator, uint256 amount);
    event RefundIssued(uint256 indexed campaignId, address indexed contributor, uint256 amount);
    event CampaignFailed(uint256 indexed campaignId, uint256 totalRaised, uint256 goalAmount);

    // ============================================
    // MODIFIERS
    // ============================================

    modifier campaignExists(uint256 _campaignId) {
        require(_campaignId > 0 && _campaignId <= campaignCounter, "Campaign does not exist");
        _;
    }

    modifier onlyCreator(uint256 _campaignId) {
        require(campaigns[_campaignId].creator == msg.sender, "Only creator can call this");
        _;
    }

    modifier onlyContributor(uint256 _campaignId) {
        require(contributions[_campaignId][msg.sender] > 0, "Only contributors can call this");
        _;
    }

    modifier isActive(uint256 _campaignId) {
        require(campaigns[_campaignId].status == CampaignStatus.Active, "Campaign is not active");
        _;
    }

    // ============================================
    // MAIN FUNCTIONS
    // ============================================

    /// @notice Buat campaign crowdfunding baru
    function createCampaign(
        string memory _title,
        string memory _description,
        uint256 _goalAmount,
        uint256 _durationDays
    ) public {
        require(_goalAmount >= MIN_GOAL, "Goal must be >= MIN_GOAL");
        require(_durationDays * 1 days >= MIN_DURATION, "Duration too short");
        require(_durationDays * 1 days <= MAX_DURATION, "Duration too long");

        campaignCounter++;
        uint256 deadline = block.timestamp + (_durationDays * 1 days);

        campaigns[campaignCounter] = Campaign({
            campaignId: campaignCounter,
            creator: msg.sender,
            title: _title,
            description: _description,
            goalAmount: _goalAmount,
            currentAmount: 0,
            deadline: deadline,
            createdAt: block.timestamp,
            status: CampaignStatus.Active,
            contributorCount: 0
        });

        creatorCampaigns[msg.sender].push(campaignCounter);
        emit CampaignCreated(campaignCounter, msg.sender, _title, _goalAmount, deadline);
    }

    /// @notice Kontribusi ETH ke campaign
    function contribute(uint256 _campaignId)
        public
        payable
        campaignExists(_campaignId)
        isActive(_campaignId)
    {
        Campaign storage campaign = campaigns[_campaignId];
        require(block.timestamp < campaign.deadline, "Campaign deadline passed");
        require(msg.value >= MIN_CONTRIBUTION, "Contribution too small");
        require(campaign.creator != msg.sender, "Creator cannot contribute");

        contributions[_campaignId][msg.sender] += msg.value;
        campaign.currentAmount += msg.value;

        if (!hasContributed[_campaignId][msg.sender]) {
            hasContributed[_campaignId][msg.sender] = true;
            campaign.contributorCount++;
        }

        if (campaign.currentAmount >= campaign.goalAmount) {
            campaign.status = CampaignStatus.Successful;
            emit CampaignSuccessful(_campaignId, campaign.currentAmount);
        }

        emit ContributionMade(_campaignId, msg.sender, msg.value, campaign.currentAmount);
    }

    /// @notice Creator claim dana setelah campaign sukses
    function claimFunds(uint256 _campaignId)
        public
        campaignExists(_campaignId)
        onlyCreator(_campaignId)
    {
        Campaign storage campaign = campaigns[_campaignId];
        require(campaign.status == CampaignStatus.Successful, "Campaign not successful");

        campaign.status = CampaignStatus.Claimed;
        uint256 amount = campaign.currentAmount;

        (bool success, ) = payable(msg.sender).call{value: amount}("");
        require(success, "Transfer failed");

        emit FundsClaimed(_campaignId, msg.sender, amount);
    }

    /// @notice Kontributor refund jika campaign gagal
    function refund(uint256 _campaignId)
        public
        campaignExists(_campaignId)
        onlyContributor(_campaignId)
    {
        Campaign storage campaign = campaigns[_campaignId];
        require(campaign.status == CampaignStatus.Failed, "Campaign not failed");

        uint256 amount = contributions[_campaignId][msg.sender];
        contributions[_campaignId][msg.sender] = 0;

        (bool success, ) = payable(msg.sender).call{value: amount}("");
        require(success, "Refund failed");

        emit RefundIssued(_campaignId, msg.sender, amount);
    }

    /// @notice Cek dan update status campaign
    function checkCampaign(uint256 _campaignId) public campaignExists(_campaignId) {
        Campaign storage campaign = campaigns[_campaignId];
        if (campaign.status != CampaignStatus.Active) return;
        if (block.timestamp < campaign.deadline) return;

        if (campaign.currentAmount >= campaign.goalAmount) {
            campaign.status = CampaignStatus.Successful;
            emit CampaignSuccessful(_campaignId, campaign.currentAmount);
        } else {
            campaign.status = CampaignStatus.Failed;
            emit CampaignFailed(_campaignId, campaign.currentAmount, campaign.goalAmount);
        }
    }

    // ============================================
    // VIEW FUNCTIONS
    // ============================================

    function getCampaignDetails(uint256 _campaignId)
        public
        view
        campaignExists(_campaignId)
        returns (Campaign memory)
    {
        return campaigns[_campaignId];
    }

    function getMyContribution(uint256 _campaignId) public view returns (uint256) {
        return contributions[_campaignId][msg.sender];
    }

    function getMyCampaigns() public view returns (uint256[] memory) {
        return creatorCampaigns[msg.sender];
    }

    function getTimeRemaining(uint256 _campaignId)
        public
        view
        campaignExists(_campaignId)
        returns (uint256)
    {
        if (block.timestamp >= campaigns[_campaignId].deadline) return 0;
        return campaigns[_campaignId].deadline - block.timestamp;
    }

    function getContractBalance() public view returns (uint256) {
        return address(this).balance;
    }
}

Koneksi dengan Sesi 1

Contract ini adalah implementasi lengkap dari Final Challenge CrowdFund di Sesi 1. Jika Anda sudah membuat versi sendiri di Remix, Anda bisa gunakan versi Anda sendiri!

---

Step 10: Compile Contract

Compile smart contract Anda:

npx hardhat compile

Output yang diharapkan:

Compiled 1 Solidity file successfully

Hasil compilation:

• File bytecode dan ABI dibuat di folder artifacts/
• TypeScript types di-generate otomatis
• Error akan ditampilkan jika ada masalah di code

Check hasil compilation:

ls -la artifacts/contracts/CrowdFund.sol/

Anda akan melihat file CrowdFund.json yang berisi ABI dan bytecode.

---

Step 11: Buat Deployment Script

1. Buat file ignition/modules/CrowdFund.ts:

mkdir -p ignition/modules

2. Isi dengan deployment script:

Buka/buat file ignition/modules/CrowdFund.ts:

import { buildModule } from "@nomicfoundation/hardhat-ignition/modules";

/**
 * Hardhat Ignition deployment module untuk CrowdFund
 */
const CrowdFundModule = buildModule("CrowdFundModule", (m) => {
  // Deploy CrowdFund contract
  const crowdFund = m.contract("CrowdFund");

  // Return deployed contract instance
  return { crowdFund };
});

export default CrowdFundModule;

Penjelasan:

• buildModule = fungsi Hardhat Ignition untuk membuat deployment module
• m.contract("CrowdFund") = deploy contract CrowdFund
• Contract tidak butuh constructor parameters
• Return instance untuk digunakan di script lain

---

Step 12: Dapatkan Testnet ETH

Untuk deploy ke testnet, Anda butuh ETH testnet:

Cara mendapatkan Sepolia ETH:

Opsi 1: Sepolia Faucet (sepoliafaucet.com)

1. Kunjungi https://sepoliafaucet.com
2. Paste address wallet Anda
3. Klik "Request tokens"
4. Tunggu 30 detik - 1 menit

Opsi 2: Alchemy Sepolia Faucet

1. Kunjungi https://sepoliafaucet.com
2. Login dengan akun Alchemy (gratis)
3. Paste address wallet Anda
4. Klik "Send Me ETH"

Opsi 3: Infura Sepolia Faucet

1. Kunjungi https://www.infura.io/faucet/sepolia
2. Login dengan akun Infura (gratis)
3. Paste address wallet Anda
4. Request ETH testnet

Check balance di MetaMask - pastikan ada ETH testnet sebelum deploy.

---

Step 13: Deploy ke Sepolia Testnet!

Deploy contract ke Sepolia:

npx hardhat ignition deploy ignition/modules/CrowdFund.ts --network sepolia

Proses deployment:

✔ Confirm deploy to network sepolia (11155111)? … yes

Hardhat Ignition 🚀

Deploying [ CrowdFundModule ]

Batch #1
  Executed CrowdFundModule#CrowdFund

[ CrowdFundModule ] successfully deployed 🚀

Deployed Addresses

CrowdFundModule#CrowdFund - 0x1234567890abcdef1234567890abcdef12345678

🎉 SAVE CONTRACT ADDRESS INI!

• Copy address yang muncul
• Anda akan butuh untuk interact dengan contract

---

Step 14: Verify Contract di Block Explorer

Verify contract agar orang lain bisa lihat source code:

npx hardhat verify --network sepolia 0xYourContractAddress

Ganti 0xYourContractAddress dengan address contract Anda!

Output:

=== Blockscout ===

📤 Submitted source code for verification on Blockscout:

  contracts/CrowdFund.sol:CrowdFund
  Address: 0x1234...

⏳ Waiting for verification result...

✅ Contract verified successfully on Blockscout!

  contracts/CrowdFund.sol:CrowdFund
  Explorer: https://eth-sepolia.blockscout.com/address/0x1234...#code

Buka link Explorer tersebut di browser - Anda akan lihat contract verified dengan source code!

Etherscan vs Blockscout

Hardhat 3 akan mencoba verify di Etherscan, Blockscout, dan Sourcify sekaligus. Jika Etherscan gagal (karena perlu API key V2), Blockscout biasanya tetap berhasil. Blockscout adalah block explorer open-source yang gratis!

---

Interact dengan CrowdFund Contract

Step 15: Buat Interaction Script

1. Buat file scripts/interact.ts:

import { network } from "hardhat";
import { parseEther, formatEther } from "viem";

// Contract address hasil deployment
const CONTRACT_ADDRESS = "0xYourContractAddressHere";

// Connect ke network dan dapatkan viem instance
const { viem } = await network.connect();
const publicClient = await viem.getPublicClient();

// Get contract instance menggunakan Viem (Hardhat 3)
const crowdFund = await viem.getContractAt(
  "CrowdFund",
  CONTRACT_ADDRESS
);

console.log("CrowdFund contract:", CONTRACT_ADDRESS);
console.log("");

// 1. Buat campaign baru
console.log("📝 Creating a new campaign...");
const txHash = await crowdFund.write.createCampaign([
  "Bangun Perpustakaan Web3",           // title
  "Dana untuk buku dan resource web3",  // description
  parseEther("0.05"),                   // goal: 0.05 ETH
  7n,                                   // durasi: 7 hari (bigint)
]);
console.log("✅ Campaign created! Transaction:", txHash);
console.log("");

// Tunggu transaction di-mine
await publicClient.waitForTransactionReceipt({ hash: txHash });

// 2. Lihat campaign counter
console.log("📊 Checking campaign counter...");
const campaignCount = await crowdFund.read.campaignCounter();
console.log("Total campaigns:", campaignCount.toString());
console.log("");

// 3. Lihat detail campaign
console.log("🔍 Getting campaign details...");
const campaign = await crowdFund.read.getCampaignDetails([1n]);
console.log("Title:", campaign.title);
console.log("Goal:", formatEther(campaign.goalAmount), "ETH");
console.log("Current:", formatEther(campaign.currentAmount), "ETH");
console.log("Status:", ["Active", "Successful", "Failed", "Claimed"][Number(campaign.status)]);
console.log("Contributors:", campaign.contributorCount.toString());
console.log("");

// 4. Lihat sisa waktu
console.log("⏰ Checking time remaining...");
const timeLeft = await crowdFund.read.getTimeRemaining([1n]);
const daysLeft = Number(timeLeft) / 86400;
console.log("Time remaining:", daysLeft.toFixed(2), "days");
console.log("");

// 5. Lihat saldo contract
console.log("💰 Contract balance...");
const balance = await crowdFund.read.getContractBalance();
console.log("Balance:", formatEther(balance), "ETH");
console.log("");

// 6. Lihat campaign yang saya buat
console.log("📋 My campaigns...");
const myCampaigns = await crowdFund.read.getMyCampaigns();
console.log("Campaign IDs:", myCampaigns.map((id: bigint) => id.toString()));

Penjelasan Viem di Hardhat 3:

Hardhat 3 menggunakan top-level await (ESM) dan network.connect() untuk mendapatkan Viem instance:

// Cara Hardhat 3 (Viem)
import { network } from "hardhat";
const { viem } = await network.connect();

// Dapatkan clients
const publicClient = await viem.getPublicClient();   // untuk read
const [walletClient] = await viem.getWalletClients(); // untuk write

// Get contract instance
const contract = await viem.getContractAt("ContractName", "0x...");

Aksi	Syntax Viem	Penjelasan
Read data	contract.read.functionName([args])	Call view/pure function
Send tx	contract.write.functionName([args])	Kirim transaction, return tx hash
Tunggu tx	publicClient.waitForTransactionReceipt({ hash })	Tunggu sampai di-mine
ETH → wei	parseEther("1.0")	Convert string ETH ke bigint wei
wei → ETH	formatEther(amount)	Convert bigint wei ke string ETH
Angka besar	42n	Pakai BigInt literal (akhiran n)

2. Update CONTRACT_ADDRESS dengan address contract Anda

3. Run script:

npx hardhat run scripts/interact.ts --network sepolia

Output:

CrowdFund contract: 0x1234...

📝 Creating a new campaign...
✅ Campaign created! Transaction: 0xabc...

📊 Checking campaign counter...
Total campaigns: 1

🔍 Getting campaign details...
Title: Bangun Perpustakaan Web3
Goal: 0.05 ETH
Current: 0.0 ETH
Status: Active
Contributors: 0

⏰ Checking time remaining...
Time remaining: 7.00 days

💰 Contract balance...
Balance: 0.0 ETH

📋 My campaigns...
Campaign IDs: [1]

Untuk Test Contribute & Refund

Script di atas hanya membuat campaign. Untuk test contribute, Anda perlu akun berbeda dari creator (karena creator tidak boleh kontribusi ke campaign sendiri). Coba buat script kedua atau test di Remix dengan multiple accounts!

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Hardhat Commands Cheat Sheet

# Compile contracts
npx hardhat compile

# Clean artifacts
npx hardhat clean

# Run tests (jika ada)
npx hardhat test

# Deploy menggunakan Ignition
npx hardhat ignition deploy ignition/modules/YourModule.ts --network <network-name>

# Verify contract
npx hardhat verify --network <network-name> <contract-address>

# Run custom script
npx hardhat run scripts/your-script.ts --network <network-name>

# Check Hardhat version
npx hardhat --version

# Get help
npx hardhat help

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Best Practices

Security

• ✅ Selalu gunakan .env untuk private keys
• ✅ Tambahkan .env ke .gitignore
• ✅ Jangan hardcode private keys di code
• ✅ Gunakan testnet wallet, bukan wallet utama
• ✅ Test di testnet sebelum deploy ke mainnet

Code Quality

• ✅ Gunakan TypeScript untuk type safety
• ✅ Enable compiler optimizer
• ✅ Write tests untuk setiap fungsi
• ✅ Verify contracts di block explorer
• ✅ Add comments di code

Project Structure

• ✅ Organize contracts di folder yang jelas
• ✅ Pisahkan deployment scripts per contract
• ✅ Buat folder tests/ untuk test files
• ✅ Gunakan Git untuk version control

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Troubleshooting

Error: "Module not found"

# Install missing dependencies
npm install

Error: "Invalid private key"

# Check .env file
# Pastikan private key tanpa "0x" di awal
PRIVATE_KEY=abc123...  # ✅ Benar
PRIVATE_KEY=0xabc123...  # ❌ Salah

Error: "Insufficient funds"

# Dapatkan testnet ETH dari faucet
# Check balance di MetaMask

Error: "Network not configured"

# Check hardhat.config.ts
# Pastikan network name sesuai dengan --network flag

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Apa yang Sudah Dipelajari

Setup Professional:

• ✅ Install Hardhat 3 (versi terbaru 2025)
• ✅ Buat TypeScript project dengan ESM
• ✅ Konfigurasi Sepolia testnet
• ✅ Secure private keys dengan dotenv

Development Workflow:

• ✅ Compile CrowdFund contract dengan optimization
• ✅ Deploy menggunakan Hardhat Ignition
• ✅ Verify di block explorer
• ✅ Interact dengan TypeScript scripts (create campaign, check details)

Modern Features:

• ✅ Viem library (modern alternative ethers.js)
• ✅ TypeScript type safety
• ✅ Plugin architecture
• ✅ Chain descriptors

CrowdFund Contract:

• ✅ Deploy Final Challenge Sesi 1 secara professional
• ✅ Interact dengan crowdfunding functions via script
• ✅ Verifikasi contract di Etherscan

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Langkah Selanjutnya

Setelah menguasai Hardhat, lanjut ke:

1. Writing Tests - Buat automated tests untuk contracts
2. Token Standards - Deploy ERC-20, ERC-721 tokens
3. Advanced Deployment - Multi-contract deployments
4. Gas Optimization - Optimize contract untuk hemat gas
5. Security Auditing - Best practices & common vulnerabilities

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Resources

• Hardhat Documentation
• Hardhat 3 Release Notes
• Viem Documentation
• Solidity Documentation
• ETHJKT Discord

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Ready to build with Hardhat 3! 🚀