Whitelist using a MerkleTree

Simple code template for whitelisting addresses using a merkletree. Mint function is being called with MetaMask and ethers.js. Express.js is used as backend.

If you are in search of a version where it is possible to whitelist different amount of NFT mints per address, check out branch v2.0

Prerequisites

Add localhost network to MetaMask

Name: Localhost 8545
RPC-URL: http://localhost:8545
Chain ID: 1337
Currency Symbol: ETH

If you want to deploy the contract to Rinkeby, or fork the ETH mainnet for testing, create a .env file in the hardhat directory and include the neccessary API Keys.

API_MAINNET = "YOUR_MAINNET_API_KEY"
API_RINKEBY = "RINKEBY_API_KEY"
...

If not, just comment the stuff out (or delete it) where you need an API key in hardhat.config.js. If you dont do this, you wont be able to start a hardhat node.

Installation

Clone this repo and run

npm install

In the root and hardhat directory

Backend

Add all addresses you want to whitelist in setMerkleTree.js

const leaves = [
  "ADDRESS1",
  "ADDRESS2",
  "ADDRESS3",
].map((x) => keccak256(x));

Start your backend server

nodemon server.js

It should show you your MerkleTree root in the console, you will need that later for contract deployment

Hardhat

Open another terminal, cd to your hardhat directory and start a local hardhat node

npx hardhat node

Open a third terminal instance and start the hardhat console

npx hardhat console --network localhost

In the hardhat console, deploy MerkleTree.sol

Contract = await ethers.getContractFactory("MerkleTree");
contract = await Contract.deploy("Name", "Symbol", "YOUR_MERKLE_ROOT");

You will see the deployed contract address in your console. Update the contract address in client.js to the correct one!

Funding your account

To fund your localhost account with ether

await network.provider.send("hardhat_setBalance", [ "YOUR_ACCOUNT_ADDRESS", "0x1000000000000000000",]);

After executing that command in your hardhat console, reload your MetaMask (e.g. by switching the network from localhost to mainnet and back to localhost). MetaMask doesnt update balances automatically.

Interact with MerkleTree.sol

Set your MetaMask network to Localhost
Open http://localhost:8080/
Open the Browser console to see if any errors come up
Click on CONNECT, you should see your account address in the browser console
Call smart contract, if your address is whitelisted MetaMask should pop up, if not, you should see an error in the console

If the minting worked, you should see a log of the transfer event in your browser console. To see your minted NFT in your wallet, click on "Import Tokens" in MetaMask and add the contract address

Common errors

If you restart your local hardhat node and try to mint with the same MetaMask account, you will get an invalid nonce error. The cached transaction history in Metamask does not match the network’s history. To fix this, reset your MetaMask account or change the accounts nonce in your hardhat network by running this command in your hardhat console:

await network.provider.send("hardhat_setNonce", [
  "YOUR_ACCOUNT",
  "0x4",
]);

In the above example the nonce is set to 4.

beskay / MerkleWhitelist