Building a Full Stack NFT Minting DApp Using Hardhat, Ethers.js, Next.js, and TailwindCSS

Prerequisites To be successful in this guide, you must have the following: installed on your machine Node.js wallet extension installed as a browser extension Metamask Resources Solidity docs : An introduction to Solidity with simple examples Solidity by example Buildspace is a startup that helps people learn to build crypto-related projects for free. Buildspace This project is based on the buildspace project . Mint your own NFT collection and ship a Web3 app to show them off There are many other projects like this on buildspace and I highly recommend you to check them out. You can also get cool NFTs for completing a project. Here is the one I got for completing this project About the project In this post, we will build a full-stack NFT minting dapp using , , , , and . Solidity Hardhat ethers.js Next.js TailwindCSS To view the final source code for this project, visit this repo To view the deployed site visit this website Project setup To get started we need to create a hardhat project. To do so, open your terminal. Create or change into a new empty directory and run the following command: npm install ethers hardhat @nomiclabs/hardhat-waffle \ ethereum-waffle chai @nomiclabs/hardhat-ethers \ @openzeppelin/contracts dotenv This will install the dependencies for setting up a hardhat project and some other dependencies for the project. Next, initialize a new Hardhat development environment from the root of your project. To do so, run the following command in your terminal: npx hardhat The output will be similar to what is shown below. Select to create a new hardhat project in your directory. Create a basic sample project What do you want to do? … Create a basic sample project Create an advanced sample project . . . Now you should see the following files and folders created for you in your root directory: The entirety of your Hardhat setup (i.e. your config, plugins, and custom tasks) is contained in this file. hardhat.config.js - A folder containing a script named sample-script.js that will deploy your smart contract when executed. scripts - A folder containing an example testing script. test - A folder holding an example Solidity smart contract. contracts - Now, we need to create a new Next.js project for the frontend of the dapp. To do so, run the following command in your terminal: npx create-next-app -e with-tailwindcss client This will create a new Next project using tailwindcss for styling in a folder 'client'. After this install dependencies for the frontend inside the folder. To do this run the following command in your terminal: client cd client npm install axios ethers react-loader-spinner Creating an Ethereum API key using Alchemy Alchemy is a blockchain developer platform focused on making blockchain development easy. They've built a suite of developer tools, enhanced APIs, and superior node infrastructure to make building and running blockchain applications seamless. To create an API key follow the video below. Things to note: Select the network as rinkeby. Copy the HTTP key after the creation of the app on alchemy. https://www.youtube.com/watch?v=tfggWxfG9o0 Next, create a file to store your and your .env Alchemy key Account Private Key ALCHEMY_RINKEBY_URL = "ALCHEMY_HTTP_API_KEY" ACCOUNT_KEY = "YOUR_ACCOUNT_PRIVATE_KEY : Do not push the file to GitHub as it contains your private data. Important .env Updating hardhat.config.js After this, update the configuration at hardhat.config.js with the following: require('@nomiclabs/hardhat-waffle') require('dotenv').config() module.exports = { solidity: '0.8.3', networks: { rinkeby: { url: process.env.ALCHEMY_RINKEBY_URL, accounts: [process.env.ACCOUNT_KEY], }, }, } Creating Smart Contract logic Next, we'll create our smart contracts! We'll create an NFT contract for the creation of NFT assets. Create a new file in the contracts directory named . Here, add the following code: EternalNFT.sol You can view the gist at EternalNFT.sol //SPDX-License-Identifier: MIT pragma solidity 0.8.3; import "@openzeppelin/contracts/utils/Counters.sol"; import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol"; import { Base64 } from "./libraries/Base64.sol"; contract EternalNFT is ERC721URIStorage { using Counters for Counters.Counter; Counters.Counter private _tokenId; string public collectionName; string public collectionSymbol; string baseSvg = " .base { fill: white; font-family: serif; font-size: 24px; } "; string[] element = [ 'Fire', 'Wind', 'Wave', 'Earth', 'Thunder', 'Space', 'Time' ]; string[] weapon = [ 'Sword', 'Spear', 'Shield', 'Hammer', 'Saber', 'Axe', 'Bow' ]; string[] rank = [ 'Lord', 'King', 'Emperor', 'Venerable', 'Ancestor', 'Saint', 'God' ]; constructor() ERC721("EternalNFT", "ENFT") { collectionName = name(); collectionSymbol = symbol(); } function random(string memory _input) internal pure returns(uint256) { return uint256(keccak256(abi.encodePacked(_input))); } function pickFirstWord(uint256 tokenId) public view returns(string memory) { uint256 rand = random(string(abi.encodePacked("element", Strings.toString(tokenId)))); rand = rand % element.length; return element[rand]; } function pickSecondWord(uint256 tokenId) public view returns(string memory) { uint256 rand = random(string(abi.encodePacked("weapon", Strings.toString(tokenId)))); rand = rand % weapon.length; return weapon[rand]; } function pickThirdWord(uint256 tokenId) public view returns(string memory) { uint256 rand = random(string(abi.encodePacked("rank", Strings.toString(tokenId)))); rand = rand % rank.length; return rank[rand]; } function createEternalNFT() public returns(uint256) { uint256 newItemId = _tokenId.current(); string memory first = pickFirstWord(newItemId); string memory second = pickSecondWord(newItemId); string memory third = pickThirdWord(newItemId); string memory combinedWord = string(abi.encodePacked(first,second,third)); string memory finalSvg = string(abi.encodePacked(baseSvg, first, second, third, " ")); string memory json = Base64.encode( bytes( string( abi.encodePacked( '{"name": "', combinedWord, '", "description": "A highly acclaimed collection Eternal Warriors", "image": "data:image/svg+xml;base64,', Base64.encode(bytes(finalSvg)), '"}' ) ) ) ); string memory finalTokenURI = string(abi.encodePacked( "data:application/json;base64,", json )); _safeMint(msg.sender, newItemId); _setTokenURI(newItemId, finalTokenURI); _tokenId.increment(); return newItemId; } } In this contract, we are inheriting from the and implemented by ERC721ERC721URIStorage.sol Counters.sol OpenZeppelin For the that is inherited by the contract, create a folder inside the contracts folder. Inside the libraries, folder create a file add the following code: Base64 library libraries Base64.sol You can view the gist at Base64.sol /** *Submitted for verification at Etherscan.io on 2021-09-05 */ // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; /// [MIT License] /// @title Base64 /// @notice Provides a function for encoding some bytes in base64 /// @author Brecht Devos library Base64 { bytes internal constant TABLE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; /// @notice Encodes some bytes to the base64 representation function encode(bytes memory data) internal pure returns (string memory) { uint256 len = data.length; if (len == 0) return ""; // multiply by 4/3 rounded up uint256 encodedLen = 4 * ((len + 2) / 3); // Add some extra buffer at the end bytes memory result = new bytes(encodedLen + 32); bytes memory table = TABLE; assembly { let tablePtr := add(table, 1) let resultPtr := add(result, 32) for { let i := 0 } lt(i, len) { } { i := add(i, 3) let input := and(mload(add(data, i)), 0xffffff) let out := mload(add(tablePtr, and(shr(18, input), 0x3F))) out := shl(8, out) out := add( out, and(mload(add(tablePtr, and(shr(12, input), 0x3F))), 0xFF) ) out := shl(8, out) out := add( out, and(mload(add(tablePtr, and(shr(6, input), 0x3F))), 0xFF) ) out := shl(8, out) out := add( out, and(mload(add(tablePtr, and(input, 0x3F))), 0xFF) ) out := shl(224, out) mstore(resultPtr, out) resultPtr := add(resultPtr, 4) } switch mod(len, 3) case 1 { mstore(sub(resultPtr, 2), shl(240, 0x3d3d)) } case 2 { mstore(sub(resultPtr, 1), shl(248, 0x3d)) } mstore(result, encodedLen) } return string(result); } } Testing the Smart Contracts Now the smart contract code and environment are complete and we can try testing it out. To do so, we can create a local test to run through much of the functionality, like checking for name, symbol, and address of token, minting a token, etc. To create the test, open test/sample-test.js and update it with the following code: You can view the gist at sample-test.js const { assert } = require('chai') describe('EternalNFT Contract', async () => { let nft let nftContractAddress let tokenId // Deploys the EternalNFT contract and the EternalMarket contract before each test beforeEach('Setup Contract', async () => { const EternalNFT = await ethers.getContractFactory('EternalNFT') nft = await EternalNFT.deploy() await nft.deployed() nftContractAddress = await nft.address }) // Tests address for the EternalNFT contract it('Should have an address', async () => { assert.notEqual(nftContractAddress, 0x0) assert.notEqual(nftContractAddress, '') assert.notEqual(nftContractAddress, null) assert.notEqual(nftContractAddress, undefined) }) // Tests name for the token of EternalNFT contract it('Should have a name', async () => { // Returns the name of the token const name = await nft.collectionName() assert.equal(name, 'EternalNFT') }) // Tests symbol for the token of EternalNFT contract it('Should have a symbol', async () => { // Returns the symbol of the token const symbol = await nft.collectionSymbol() assert.equal(symbol, 'ENFT') }) // Tests for NFT minting function of EternalNFT contract using tokenID of the minted NFT it('Should be able to mint NFT', async () => { // Mints a NFT let txn = await nft.createEternalNFT() let tx = await txn.wait() // tokenID of the minted NFT let event = tx.events[0] let value = event.args[2] tokenId = value.toNumber() assert.equal(tokenId, 0) // Mints another NFT txn = await nft.createEternalNFT() tx = await txn.wait() // tokenID of the minted NFT event = tx.events[0] value = event.args[2] tokenId = value.toNumber() assert.equal(tokenId, 1) }) }) To run the test, run the following command from your terminal at the root of your project: npx hardhat test Deploying the contracts to the Rinkeby Network When we created the project, Hardhat created an example deployment script at . scripts/sample-script.js To make the purpose of this script clear, delete and create . scripts/sample-script.js scripts/deploy.js To deploy the contracts add the following code inside : depoly.js const main = async () => { const nftContractFactory = await ethers.getContractFactory('EternalNFT') const nftContract = await nftContractFactory.deploy() await nftContract.deployed() console.log('Contract deployed to:', nftContract.address) } const runMain = async () => { try { await main() process.exit(0) } catch (error) { console.log(error) process.exit(1) } } runMain() To deploy the contract to the rinkeby network run the following command in your terminal: npx hardhat run scripts/deploy.js --network rinkeby This will deploy the contract to the rinkeby network and output the address at which the contract is deployed in the terminal. Building the frontend Now that the smart contract is working and ready to go, we can start building out the UI. First, we need to connect the frontend to the smart contract, so it can interact with the data from the blockchain using the functions in the smart contracts. For this we need to do the following: Create a folder inside the folder and copy and paste the file inside the folder. utils client artifacts/contracts/EternalNFT.sol/EternalNFT.json utils Create a file inside the folder and add the following code inside it. config.js client export const nftContractAddress = "DEPLOYED_CONTRACT_ADDRES" Replace the with the deployed contract address from the terminal when deploying the smart contract. DEPLOYED_CONTRACT_ADDRES Next, to set up the frontend go to and update it with the following code: client/pages/index.js You can view the gist at index.js import { useState, useEffect } from 'react' import { nftContractAddress } from '../config.js' import { ethers } from 'ethers' import axios from 'axios' import Loader from 'react-loader-spinner' import NFT from '../utils/EternalNFT.json' const mint = () => { const [mintedNFT, setMintedNFT] = useState(null) const [miningStatus, setMiningStatus] = useState(null) const [loadingState, setLoadingState] = useState(0) const [txError, setTxError] = useState(null) const [currentAccount, setCurrentAccount] = useState('') const [correctNetwork, setCorrectNetwork] = useState(false) // Checks if wallet is connected const checkIfWalletIsConnected = async () => { const { ethereum } = window if (ethereum) { console.log('Got the ethereum obejct: ', ethereum) } else { console.log('No Wallet found. Connect Wallet') } const accounts = await ethereum.request({ method: 'eth_accounts' }) if (accounts.length !== 0) { console.log('Found authorized Account: ', accounts[0]) setCurrentAccount(accounts[0]) } else { console.log('No authorized account found') } } // Calls Metamask to connect wallet on clicking Connect Wallet button const connectWallet = async () => { try { const { ethereum } = window if (!ethereum) { console.log('Metamask not detected') return } let chainId = await ethereum.request({ method: 'eth_chainId' }) console.log('Connected to chain:' + chainId) const rinkebyChainId = '0x4' const devChainId = 1337 const localhostChainId = `0x${Number(devChainId).toString(16)}` if (chainId !== rinkebyChainId && chainId !== localhostChainId) { alert('You are not connected to the Rinkeby Testnet!') return } const accounts = await ethereum.request({ method: 'eth_requestAccounts' }) console.log('Found account', accounts[0]) setCurrentAccount(accounts[0]) } catch (error) { console.log('Error connecting to metamask', error) } } // Checks if wallet is connected to the correct network const checkCorrectNetwork = async () => { const { ethereum } = window let chainId = await ethereum.request({ method: 'eth_chainId' }) console.log('Connected to chain:' + chainId) const rinkebyChainId = '0x4' const devChainId = 1337 const localhostChainId = `0x${Number(devChainId).toString(16)}` if (chainId !== rinkebyChainId && chainId !== localhostChainId) { setCorrectNetwork(false) } else { setCorrectNetwork(true) } } useEffect(() => { checkIfWalletIsConnected() checkCorrectNetwork() }, []) // Creates transaction to mint NFT on clicking Mint Character button const mintCharacter = async () => { try { const { ethereum } = window if (ethereum) { const provider = new ethers.providers.Web3Provider(ethereum) const signer = provider.getSigner() const nftContract = new ethers.Contract( nftContractAddress, NFT.abi, signer ) let nftTx = await nftContract.createEternalNFT() console.log('Mining....', nftTx.hash) setMiningStatus(0) let tx = await nftTx.wait() setLoadingState(1) console.log('Mined!', tx) let event = tx.events[0] let value = event.args[2] let tokenId = value.toNumber() console.log( `Mined, see transaction: https://rinkeby.etherscan.io/tx/${nftTx.hash}` ) getMintedNFT(tokenId) } else { console.log("Ethereum object doesn't exist!") } } catch (error) { console.log('Error minting character', error) setTxError(error.message) } } // Gets the minted NFT data const getMintedNFT = async (tokenId) => { try { const { ethereum } = window if (ethereum) { const provider = new ethers.providers.Web3Provider(ethereum) const signer = provider.getSigner() const nftContract = new ethers.Contract( nftContractAddress, NFT.abi, signer ) let tokenUri = await nftContract.tokenURI(tokenId) let data = await axios.get(tokenUri) let meta = data.data setMiningStatus(1) setMintedNFT(meta.image) } else { console.log("Ethereum object doesn't exist!") } } catch (error) { console.log(error) setTxError(error.message) } } return ( Mint your Eternal Domain NFT! {currentAccount === '' ? ( Connect Wallet ) : correctNetwork ? ( Mint Character ) : ( ---------------------------------------- Please connect to the Rinkeby Testnet and reload the page ---------------------------------------- )} View Collection on Rarible {loadingState === 0 ? ( miningStatus === 0 ? ( txError === null ? ( Processing your transaction ) : ( {txError} ) ) : ( ) ) : ( Your Eternal Domain Character )} ) } export default mint Let's discuss the code we have added to the file. index.js The code contains the following functions: : This function checks if the wallet is connected to the dapp when it loads. checkIfWalletIsConnected : This function connects the wallet to the dapp when the user clicks the button in the frontend. connectWallet Connect Wallet : This function checks if the wallet is connected to the network. If not the frontend asks the user to connect to the network and reload the page. checkCorrectNetwork rinkeby rinkeby : This function creates the transaction to mint a new NFT when the user clicks on the button. mintCharacter Mint Character : This function retrieves the data of the newly minted NFT to display it in the frontend. getMintedNFT To test the dapp in the browser, run the following command in your terminal: cd client npm run dev Next Steps Congratulations! You have deployed a full-stack NFT minting dapp to ethereum. After successfully deploying the dapp, you can host it on services like or . vercel netlify Hope you enjoyed the article! If you have any questions or comments, feel free to drop them below or reach out to me on and ! Twitter Linkedin Also Published Here