Mastering Blockchain Programming with Solidity

Updating the configuration

You can uncomment the appropriate sections present in the default Truffle configuration file. By default, the Ropsten testnet network configuration is present in the Truffle configuration file. Similarly, we have prepared the configuration for the Rinkeby testnet network:

const HDWalletProvider = require('truffle-hdwallet-provider');const infuraKey = "138bdb3fed8f4c96b812327d76be8a08";const fs = require('fs');const mnemonic = fs.readFileSync(".secret").toString().trim();......rinkeby: {  provider: () => new HDWalletProvider(mnemonic,   'https://rinkeby.infura.io/v3/${infuraKey}', 0, 20),  network_id: 4,  gas: 6000000,  gasPrice: 10000000000,  confirmations: 2,  timeoutBlocks: 200,  skipDryRun: true},

Let's understand each ...