From https://dev.to/dabit3/the-complete-guide-to-full-stack-ethereum-development-3j13
notes
Found a bug in the instructions. hardhat.config.js needs this line at the top:
require("@nomiclabs/hardhat-waffle");
Or you get issues with deploy.js on this line:
const Greeter = await hre.ethers.getContractFactory("Greeter");
because hre.ethers is undefined