Noting that hardhat.config.js is the entry point for each .js file, then remeber to import packages by the "require" syntax in the configuration file.

In this project, we will use the package hardhat-deploy to facilitate the process of contracts deployment, testing and other excellent functions. The package can be added to your working context by the following action:

yarn add --dev hardhat-deploy

where the official docs for its utilization can be found: https://github.com/wighawag/hardhat-deploy

If you are using ethers.js we recommend you also install hardhat-deploy-ethers which add extra features to access deployments as ethers contract.

Since hardhat-deploy-ethers is a fork of @nomiclabs/hardhat-ethers and that other plugin might have an hardcoded dependency on @nomiclabs/hardhat-ethers the best way to install hardhat-deploy-ethers and ensure compatibility is the following:

yarn add --dev  @nomiclabs/hardhat-ethers@npm:hardhat-deploy-ethers ethers

For example

"The library @chainlink/contracts, imported from contracts/FundMe.sol, is not installed. Try installing it using npm."

Solution:

yarn add --dev @chainlink/contracts

yarn add --dev @nomiclabs/hardhat-ethers@npm:hardhat-deploy-ethers ethers

Which means you then need to do require("@nomiclabs/hardhat-ethers") instead of require("hardhat-deploy-ethers") in your hardhat.config.js file.

Note that hardhat local chains and `mainnet forking chains are temporary as they are destoryed instantly at the completment of codes.

1. Create a new folder called deploy where the executions of running yarn hardhat deploy will be defined

In hardhat.config.js file, one can change the configuration of solidity from one value (e.g. "^0.8.0") to a mapping object.