Sandman Swap

Project Description

A Uniswap V1 clone for decentralized ERC20 token exchange via automated market maker on Ethereum. React frontend links to smart contracts on the local Ethereum blockchain to allow for providing/removing liquidity and swapping ETH/tokens via browser wallet.

This project was completed to gain an understanding in writing/testing/deploying smart contracts, and interacting with them from a DApp. The frontend is not intended to be fully functional but rather to provide minimal functionality to allow for usage of the smart contracts.

Setup

• Clone the project:

  git clone hhttps://github.com/nefrob/sandman-swap && cd sandman-swap
  

• Install smart contract dependencies:

  npm install
  

• Run blockchain: (initializes two accounts with 5000 ETH each):

  npm run ganache
  

  It is convienent to run the local blockchain deterministically for testing. To do so use:

  npm run ganache-det
  

• With ganache running, you can compile and deploy the contracts with:

  npm run migrate
  

• Setup and run the React Dapp from the client directory:

  cd client
  npm install
  npm start
  

• Note: MetaMask ganache account will need to be reset every time ganache is restarted to clear the old test transaction history.

Test

Unit tests are currently written for the smart contracts in this project (not the frontend components).

To run the tests from the project root directory do: npm test.

Design

MVP

• Home page
• Swap page
• Liquidity pool page
• Wallet page with currennt ETH balance and a button to connect to a wallet

PostMVP

• ETH/token exchange prices in USD (use API)
• Integration with MetaMask
• Add new token to wallet functionality
• Integration with Ethereum testnet
  • Setup frontend on CodeSandBox

Initial Wireframes

• /home:

  

• /wallet:

  

  (Uniswap V1 page for reference)

Components

Component	Description
App	Page routing, user state setup
Home	Landing page with project info
Navigation	Page routing, display header
Swap	Swapping eth/tokens for active pools
LP	Add/remove liquidity
Wallet	Setup MetaMask connection, display current holdings, add tokens to MetaMask

Sandman

This project is themed around Dream of the Endless (aka Sandman) for fun!

Resources

Dependencies

• web3.js for interaction with ethereum nodes.
• truffle for testing and deployment of contracts.
• ganache for local Ethereum blockchain testing.
• @openzeppelin/contracts for ERC standards and smart contract libraries.
• react-boostrap for styling.

Browser Wallet

MetaMask is a browser extension that allows you to interact with the Ethereum blockchain on decentralized applications. See MetaMask Docs for more information.

API

To make swap prices easier to understand, the current ETH value in USD will be fetched from CEX Rest API.

Example request: https://cex.io/api/last_price/ETH/USD returns:

{
  "lprice": "3400.36",
  "curr1": "ETH",
  "curr2": "USD"
}

Questions?

• Post issues in the Issue Tracker.