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DeFi

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ERC20 Basics

Introduction to implementing a basic ERC20 token with minting, burning, transferring, and approving functionalities.

ERC20 Basics

Most of you are probably familiar with tokens like WETH, USDT, USDC, and many others. Did you know that all of these tokens are designed by following the ERC20 standard?

In this challenge, you will implement a basic ERC20 token contract that includes minting, burning, transferring, and approving functionalities.

Objective

Your task is to:

Develop your own ERC20 token.
Deploy it to Scroll Sepolia Testnet.
And finally verify it.

If you need help with using a smart contract framework for completing this challenge, the Level Up: Build with Foundry guide might be a helpful start!

If you get stuck, feel free to ask for help in Level Up Telegram group.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

// Define your ERC20 token contract
contract MyToken is ERC20 {
    // Define the global variables for balances, total supply, name, and symbol below

    // Constructor that mints the initial supply to the deployer of the contract
    constructor(uint256 initialSupply) ERC20("MyToken", "MTK") {
        // Mint the initial supply of tokens to the deployer's address
    }

    // Function to mint new tokens to a specified address
    function mint(address to, uint256 amount) public {
        // Implement the mint function using the _mint internal function
    }

    // Function to burn tokens from a specified address
    function burn(address from, uint256 amount) public {
        // Implement the burn function using the _burn internal function
    }

    // Function to transfer tokens from the caller's address to a specified address
    function transfer(address to, uint256 amount) public override returns (bool) {
        // Implement the transfer function using the _transfer internal function
    }

    // Function to approve an address to spend a certain amount of tokens on behalf of the caller
    function approve(address spender, uint256 amount) public override returns (bool) {
        // Implement the approve function using the _approve internal function
    }

    // Function to transfer tokens from one address to another using an allowance
    function transferFrom(address from, address to, uint256 amount) public override returns (bool) {
        // Implement the transferFrom function using the _transfer and _approve internal functions
    }

    function getBalanceOf(address account) public view returns (uint256) {
        // Implement the getBalanceOf function
    }
}

Instructions

Constructor: The constructor should initialize the ERC20 token by minting the initialSupply to the deployer's address. Use the _mint function provided by the ERC20 contract.
Mint Function: Implement the mint function, which should allow you to create new tokens and assign them to a specific address. This function should call the _mint function provided by the ERC20 contract.
Burn Function: Implement the burn function, which should allow you to destroy tokens from a specific address, reducing the total supply. Use the _burn function provided by the ERC20 contract.
Transfer Function: Implement the transfer function to allow the caller to send tokens to another address. Override the transfer function and use the _transfer function from the ERC20 contract.
Approve Function: Implement the approve function, allowing the caller to authorize another address to spend a certain amount of tokens on their behalf. Override the approve function and use the _approve function from the ERC20 contract.
TransferFrom Function: Implement the transferFrom function to allow a spender to transfer tokens from one address to another, using an allowance set by the approve function. Override the transferFrom function and use the _transfer and _approve functions to implement this functionality.

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Simple Token Swap