About

• This is a test project that I've written to learn Solidity.
• It's a smart contract that allows players to enter a lottery that picks a random winner.
• The corresponding front end React UI can be viewed here.

Packages

• Web3 (JavaScript interface to Ethereum blockchain)
• Ganache (testing)
• Mocha (testing)
• Infura (deploying to test network node)
• Truffle (wallet + deployment provider)
• dotenv (storing environment variables)

To run

• npm run test - run test suite
• node deploy.js - deploy contract to test network
  • You'll need to create a .env file with your INFURA_API and Metamask wallet MNEMONIC. This is parsed in compile.js, so that the variables are available when running node deploy.js.
  • If you get an error to do with ERR_OSSL_EVP_UNSUPPORTED, it'll be due to an issue with the node version you're using. I used nvm to switch to version 15.8.0, which does the trick. Alternatively if you don't want to do this, set this option export NODE_OPTIONS=--openssl-legacy-provider.

Resources

• https://infura.io/ - Free API to connect to an Ethereum test network node
• https://rinkeby.etherscan.io/ - Etherscan Rinkeby test network
• https://faucets.chain.link/rinkeby - request test ether
• https://eth-converter.com/extended-converter.html - Eth converter