Hardhat Fund Me - Typescript Edition

This is a section of the Javascript Blockchain/Smart Contract FreeCodeCamp Course.

⌨️ (10:00:48) Lesson 7: Hardhat Fund Me

Full Repo

• Hardhat Fund Me - Typescript Edition
• Getting Started
  • Requirements
  • Quickstart
  • Typescript
• Useage
  • Testing
    • Test Coverage
• Deployment to a testnet or mainnet
  • Scripts
  • Estimate gas
    • Estimate gas cost in USD
  • Verify on etherscan
    • Typescript differences
• Linting
• Thank you!

This project is apart of the Hardhat FreeCodeCamp video.

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

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

Typescript

If you want to get to typescript and you cloned the javascript version, just run:

git checkout typescript

Useage

Deploy:

yarn hardhat deploy

Testing

yarn hardhat test

Test Coverage

yarn hardhat coverage

Deployment to a testnet or mainnet

1. Setup environment variabltes

You'll want to set your SEPOLIA_RPC_URL and PRIVATE_KEY as environment variables. You can add them to a .env file, similar to what you see in .env.example.

• PRIVATE_KEY: The private key of your account (like from metamask). NOTE: FOR DEVELOPMENT, PLEASE USE A KEY THAT DOESN'T HAVE ANY REAL FUNDS ASSOCIATED WITH IT.
  • You can learn how to export it here.
• SEPOLIA_RPC_URL: This is url of the sepolia testnet node you're working with. You can get setup with one for free from Alchemy

2. Get testnet ETH

Head over to faucets.chain.link and get some tesnet ETH. You should see the ETH show up in your metamask.

3. Deploy

yarn hardhat deploy --network sepolia

Scripts

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

yarn hardhat run scripts/fund.ts

or

yarn hardhat run scripts/withdraw.ts

Estimate gas

You can estimate how much gas things cost by running:

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 kovan contracts!

However, you can manual verify with:

yarn hardhat verify --constructor-args arguments DEPLOYED_CONTRACT_ADDRESS

Typescript differences

1. .js files are now .ts
2. We added a bunch of typescript and typing packages to our package.json. They can be installed with:
   1. yarn add @typechain/ethers-v5 @typechain/hardhat @types/chai @types/node ts-node typechain typescript
3. The biggest one being typechain
   1. This gives your contracts static typing, meaning you'll always know exactly what functions a contract can call.
   2. This gives us factories that are specific to the contracts they are factories of. See the tests folder for a version of how this is implemented.
4. We use imports instead of require. Confusing to you? Watch this video
5. Add tsconfig.json

Linting

To check linting / code formatting:

yarn lint

or, to fix:

yarn lint:fix

Thank you!

If you appreciated this, feel free to follow me or donate!

ETH/Polygon/Avalanche/etc Address: 0x9680201d9c93d65a3603d2088d125e955c73BD65