Hardhat Fund Me

TypeScript, Solidity 0.8.19 FundMe contract with Chainlink Price Feed, based upon: https://github.com/PatrickAlphaC/hardhat-fund-me-fcc

Getting Started

Requirements

git
- You'll know you did it right if you can run git --version and you see a response like git version x.x.x
Nodejs
- You'll know you've installed nodejs right if you can run:
  - node --version and get an ouput like: vx.x.x
Yarn instead of npm
- You'll know you've installed yarn right if you can run:
  - yarn --version and get an output like: x.x.x
  - You might need to install it with npm or corepack

Quickstart

Setup Development Environment

Clone the repository and install dependencies:

git clone --branch typescript https://github.com/coldfire84/hardhat-fund-me
cd hardhat-fund-me
yarn
yarn typechain

Create .env file

Use the supplied .env.template file to create a new .env file.

Mandatory environment variables:

SEPOLIA_URL: an Alchemy RPC endpoint (or other Node as a Service), sign-up here: Alchemy

Optional environment variables:

ETHERSCAN_API_KEY: used to verify contracts on Etherscan, sign-up here: Etherscan
COINMARKETCAP_API_KEY: used for gas price estimation in FIAT, sign-up here: Coin Market Cap

Encrypt Account Private Key

Storing Private Keys in a .env file is a bad idea.

One option is to encrypt your private key, and decrypt on-demand. This repository is setup to allow either

(strongly recommended) decryption using a password supplied at runtime or stored in the .env file, via PRIVATE_KEY_PASSWORD environment variable
direct usage of the provate key via a PRIVATE_KEY environment variable (will flag a warning in the console)

You can encrypt a private key using the commands below:

export PRIVATE_KEY=<Wallet Private Key>
export PRIVATE_KEY_PASSWORD=<Desired Private Key Password>
yarn hardhat run scripts/encrypt-key.ts
export PRIVATE_KEY=
export PRIVATE_KEY_PASSWORD=
history -c

Alternatively, you can also store these keys in a third-party Key Management Service.

Useage

Deployment Scripts

hardhat-deploy will execute scripts in order (based upon file name), it will also track deployed contracts and skip them if they've already been deployed.

Local Deployment

Execute deployment using the command yarn hardhat deploy to deploy to the local hardhat network.

Testnet Deployment

You'll need to ensure you have testnet ETH and LINK

for test ETH use sepoliafaucet.com
for test LINK use faucets.chain.link

Execute deployment using the command:

export PRIVATE_KEY_PASSWORD=<Desired Private Key Password> && yarn hardhat deploy` --network <network>

Where <network> is the name of the network you want to deploy to, e.g. 'sepolia'.

Testing

yarn hardhat test

Test Coverage

yarn hardhat coverage

Linting

yarn lint

Contract Interactions

Scripts

After deploy to a testnet or local net, you can run the scripts.

yarn hardhat run scripts/fund.ts

yarn hardhat run scripts/withdraw.ts

Estimate gas

You can estimate how much gas things cost by running:

export REPORT_GAS=true && yarn hardhat test

And you'll see and output file called gas-report.txt

Estimate gas cost in USD

To get a USD estimation of gas cost, you'll need a COINMARKETCAP_API_KEY environment variable. You can get one for free from CoinMarketCap.

Then, uncomment the line coinmarketcap: COINMARKETCAP_API_KEY, in hardhat.config.ts to get the USD estimation. Just note, everytime you run your tests it will use an API call, so it might make sense to have using coinmarketcap disabled until you need it. You can disable it by just commenting the line back out.

Verify on Etherscan

If you deploy to a testnet or mainnet, you can verify it if you get an API Key from Etherscan and set it as an environemnt variable named ETHERSCAN_API_KEY. You can pop it into your .env file as seen in the .env.example.

In it's current state, if you have your api key set, it will auto verify contracts!

However, you can manually verify with:

yarn hardhat verify --constructor-args <arguments> DEPLOYED_CONTRACT_ADDRESS

coldfire84 / hardhat-fund-me