Setting up the ERC-721 Project

To setup a project that uses Hardhat for ERC-721 contract development, do the following:

Create a new directory and enter it.
```
mkdir my-nft
cd my-nft
```
Initialize a new Node.js project.
```
npm init -y
```
The directory should contain a single file called package.json.
Install Hardhat by running the following command in the my-nft directory.
```
npm install --save-dev hardhat
```
The package.json file will now have a hardhat section under devDependencies.
Create a Hardhat project by running the following command. Choose the Create an empty hardhat.config.js option.
```
npx hardhat
```
The directory will have a file called hardhat.config.js with the following contents.
```
/** @type import('hardhat/config').HardhatUserConfig */
module.exports = {
    solidity: "0.8.17",
};
```
The number 0.8.17 specifies the version of the Solidity compiler.
Install the dotenv package in your project directory.
```
npm install dotenv --save
```
Create a file called .env in the project directory with the following contents.
```
API_URL = "https://eth-goerli.g.alchemy.com/v2/your-api-key"
API_KEY = "your-api-key"
PRIVATE_KEY = "your-metamask-private-key"
```
Follow these instructions to export your private key from Metamask. The API_URL and API_KEY values need to be copied from your Alchemy account.

NOTE: If you are going to push the project code to a public Github/Gitlab repository, remember to add the .env file to your .gitignore.

Install Ethers.js by running the following command

npm install --save-dev @nomiclabs/hardhat-ethers "ethers@^5.0.0"

Update the hardhat.config.js file to have the following content.

/**
* @type import('hardhat/config').HardhatUserConfig
*/

require('dotenv').config();
require("@nomiclabs/hardhat-ethers");

const { API_URL, PRIVATE_KEY } = process.env;

module.exports = {
solidity: "0.8.17",
defaultNetwork: "goerli",
networks: {
    hardhat: {},
    goerli: {
        url: API_URL,
        accounts: [`0x${PRIVATE_KEY}`]
    }
},
}

Your ERC-721 token will be based on the implementation by OpenZeppelin. Install the Node.js package containing OpenZeppelin's contracts by running the following command in the project directory.
```
npm install @openzeppelin/contracts
```
The installed contracts can be found in the node_modules directory in your project directory. The path will be node_modules/@openzeppelin/contracts/. We will be inheriting the ERC-20 implementation at node_modules/@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol.

Ethereum Lab

Setting up the ERC-721 Project