> For the complete documentation index, see [llms.txt](https://docs.vexanium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vexanium.com/reference/smart-contract/solidity-evm/to-do-list-contract.md).

# To Do List Contract

```
mkdir eth-todo-list
cd eth-todo-list
```

```
truffle init
```

```
touch package.json
```

{% code title="package.json" %}

```
{
  "name": "eth-todo-list",
  "version": "1.0.0",
  "description": "Blockchain Todo List Powered By Ethereum",
  "main": "truffle-config.js",
  "directories": {
    "test": "test"
  },
  "scripts": {
    "dev": "lite-server",
    "test": "echo \"Error: no test specified\" && sexit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "bootstrap": "4.1.3",
    "chai": "^4.1.2",
    "chai-as-promised": "^7.1.1",
    "chai-bignumber": "^2.0.2",
    "lite-server": "^2.3.0",
    "nodemon": "^1.17.3",
    "truffle": "5.0.2",
    "truffle-contract": "3.0.6"
  }
}
```

{% endcode %}

```
npm install
```

```
touch ./contracts/TodoList.sol
```

```
// Some code
```

```solidity
pragma solidity ^0.5.0;

contract TodoList {
  uint public taskCount = 0;

  struct Task {
    uint id;
    string content;
    bool completed;
  }

  mapping(uint => Task) public tasks;

  event TaskCreated(
    uint id,
    string content,
    bool completed
  );

  event TaskCompleted(
    uint id,
    bool completed
  );

  constructor() public {
    createTask("Visit vexanium.com");
  }

  function createTask(string memory _content) public {
    taskCount ++;
    tasks[taskCount] = Task(taskCount, _content, false);
    emit TaskCreated(taskCount, _content, false);
  }

  function toggleCompleted(uint _id) public {
    Task memory _task = tasks[_id];
    _task.completed = !_task.completed;
    tasks[_id] = _task;
    emit TaskCompleted(_id, _task.completed);
  }

}v
```