LieAlbertTriAdrian / crowdfundr

Web3 implementation for a crowdfunding site on Ethereum

Advanced Sample Hardhat Project

This project demonstrates an advanced Hardhat use case, integrating other tools commonly used alongside Hardhat in the ecosystem.

The project comes with a sample contract, a test for that contract, a sample script that deploys that contract, and an example of a task implementation, which simply lists the available accounts. It also comes with a variety of other tools, preconfigured to work with the project code.

Try running some of the following tasks:

npx hardhat accounts
npx hardhat compile
npx hardhat clean
npx hardhat test
npx hardhat node
npx hardhat help
REPORT_GAS=true npx hardhat test
npx hardhat coverage
npx hardhat run scripts/deploy.ts
TS_NODE_FILES=true npx ts-node scripts/deploy.ts
npx eslint '**/*.{js,ts}'
npx eslint '**/*.{js,ts}' --fix
npx prettier '**/*.{json,sol,md,ts}' --check
npx prettier '**/*.{json,sol,md,ts}' --write
npx solhint 'contracts/**/*.sol'
npx solhint 'contracts/**/*.sol' --fix

# Testing in watch mode
npm run test-watch

Etherscan verification

To try out Etherscan verification, you first need to deploy a contract to an Ethereum network that's supported by Etherscan, such as Ropsten.

In this project, copy the .env.example file to a file named .env, and then edit it to fill in the details. Enter your Etherscan API key, your Ropsten node URL (eg from Alchemy), and the private key of the account which will send the deployment transaction. With a valid .env file in place, first deploy your contract:

hardhat run --network ropsten scripts/sample-script.ts

Then, copy the deployment address and paste it in to replace DEPLOYED_CONTRACT_ADDRESS in this command:

npx hardhat verify --network ropsten DEPLOYED_CONTRACT_ADDRESS "Hello, Hardhat!"

Performance optimizations

For faster runs of your tests and scripts, consider skipping ts-node's type checking by setting the environment variable TS_NODE_TRANSPILE_ONLY to 1 in hardhat's environment. For more details see the documentation.

Design Exercise

Smart contracts have a hard limit of 24kb. Crowdfundr hands out an NFT to everyone who contributes. However, consider how Kickstarter has multiple contribution tiers. How would you design your contract to support this, without creating three separate NFT contracts?

Assign the tiers based on the number of NFT owned by contributors / total contributions. For example if a contributor has 10 badges/NFTs, so he will be promoted to GOLD. Less than 10 --> silver. We could create a simple function to get the tier based on the number of NFTs such as

function getTier(address conttributor) Tier {
    if (num of NFTs owned < 10>) --> return silver
    else --> return gold
}