Implementing the staking pool smart contract

In this section, we will implement the staking pool smart contract for staking ERC-20 tokens; the token can be an LP token (also known as farming) or something else (also known as staking). So, the smart contract code that we will explain in this section can be used for both farming and staking purposes.

To be able to follow along, we encourage you to pull the code from the chapter09-start branch in this book’s GitHub repository at https://github.com/PacktPublishing/Building-Full-stack-DeFi-Application/.

Defining smart contract variables and implementing a constructor

We’ll start by creating a file that’s located at src/backend/contracts/StakingPool.sol for the staking pool smart contract and implement the following code to define the global variables and the UserInfo struct for the smart contract:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/access/Ownable...