To-Do List Blockchain

A simple Ethereum decentralized application (dApp) for managing to-do tasks using a Solidity smart contract, Truffle migrations, and a browser frontend connected through MetaMask.

Overview

This project demonstrates end-to-end dApp flow:

• Smart contract stores tasks on-chain
• Frontend reads and updates tasks via Web3
• MetaMask signs transactions
• Truffle handles compile, deploy, and testing

Tech Stack

• Solidity 0.5.x
• Truffle 5.0.2
• Web3.js
• @truffle/contract
• Ganache (local blockchain)
• MetaMask
• Lite Server
• Bootstrap + jQuery

Project Structure

To-Do-List-Blockchain/
	contracts/
		TodoList.sol
		Migrations.sol
	migrations/
		1_initial_migration.js
		2_deploy_contracts.js
	src/
		index.html
		app.js
		css/
		TodoList.json
	test/
		TodoList.test.js
	truffle-config.js
	bs-config.json
	package.json
	README.md

Smart Contract Features

Contract: TodoList.sol

• Stores tasks in a mapping
• Tracks taskCount
• Creates tasks with createTask(string _content)
• Toggles completion with toggleCompleted(uint _id)
• Emits events:
  • TaskCreated(uint id, string content, bool completed)
  • TaskToggled(uint id, bool completed)

Default constructor task:

• Check out Forbes.com

Prerequisites

• Node.js and npm
• Ganache running on 127.0.0.1:7545
• MetaMask browser extension

Installation

npm install

Configure Local Blockchain

This project is configured for Ganache in truffle-config.js:

• Host: 127.0.0.1
• Port: 7545
• Network ID: *

Start Ganache first, then continue.

Compile and Deploy Contract

truffle compile
truffle migrate --reset

After migration, make sure contract artifact is available to frontend in:

• build/contracts/TodoList.json

Run Frontend

npm run dev

Then open:

• http://localhost:3000

MetaMask Setup

1. Connect MetaMask to local Ganache network.
2. Import a Ganache account using its private key.
3. Approve account access when the app requests connection.

The connected wallet address appears in the UI under Account.

Usage

• Add a task from input field
• Toggle task completion via checkbox
• Transactions are written to blockchain and reflected in UI

Testing

Run Truffle tests:

truffle test

The test suite validates:

• Contract deployment
• Initial default task
• Task creation
• Task completion toggling

Notes

• The npm test script in package.json contains a typo (sexit) and does not run contract tests.
• Use truffle test directly for now.
• Frontend expects TodoList.json artifact to be available when lite-server runs.

Author

Suprit Raj