Blockchain Ethereum Contract

• Truffle Framework used to create an Ethereum app using Javascript and Solidity.
• Code from Fazt Code - see 👏 Inspiration below
• Note: to open web links in a new window use: ctrl+click on link

📄 Table of contents

• ⚡ Angular Python Charts
  • 📄 Table of contents
  • 📚 General info
  • 📷 Screenshots
  • 📶 Technologies
  • 💾 Setup
  • 🔦 Testing
  • 💻 Code Examples
  • 🆒 Features
  • 📋 Status & To-Do List
  • 👏 Inspiration
  • 📁 License
  • ✉️ Contact

📚 General info

• Ethereum blockchain app is written in Solidity, similar to Javascript
• The app is a simple todo list with title & description strings, integer id & date fields with a boolean 'done' field
• Truffle suite includes Ganache, required to run the tests

📷 Screenshots

📶 Technologies

• Truffle Suite tools for smart contracts
• @truffle/contract Ethereum contract abstraction, for Node & browser.
• Ganache framework to run Ethereum blockchain apps
• Ethereum decentralised app (DApps)
• Solidity v0.8.6 a curly-bracket language, object-oriented, high-level language for implementing smart contracts
• Javascript testing using the Mocha framework and the Chai assertion library
• Node.js v14.17.0 JavaScript runtime built on Chrome's V8 JavaScript engine.
• lite-server v2.6 node server
• Bootstrap v5 frontend framework
• Google Material Fonts
• MetaMask website & MetaMask Chrome Extension browser Ethereum wallet to use blockchain app

💾 Setup

Solidity code:

• truffle console to start Truffle command prompt
• truffle migrate to compile app

Frontend:

• npm run dev for a server-lite dev server

🔦 Testing

• truffle test to run tests on Solidity code - Ganache has to be running

💻 Code Examples

• contracts/TasksContract.sol extract - In order to make events stand out with regards to regular function calls, emit TaskCreated(var1, var2...) as opposed to just EventName() is used to "call" the TaskCreated function.

function createTask(string memory _title, string memory _description) public {
  taskCounter++;
  tasks[taskCounter] = Task(taskCounter, _title, _description, false, block.timestamp);
  emit TaskCreated(taskCounter, _title, _description, false, block.timestamp);
}

🆒 Features

• connects with MetaMask Ethereum wallet Chrome Extension - see top screen print

📋 Status & To-Do List

• Working
• To-Do: Replace Bootstrap cards etc. with new style

👏 Inspiration

• Fazt Code: Solidity & Javascript App - Ethereum Aplicacion Decentralizada in Spanish
• Aniket: ‘emit’ keyword in Solidity
• Ethereum questions: Smart contract now vs javascript now explains how Javascript's timestamp is always a factor of 1000 larger than the one used by Solidity

📁 License

• N/A

✉️ Contact

• Repo created by ABateman, email: [email protected]