Simple Todo App Backend CRUD with fs module

Certainly! Below is a simple TODO app backend using Node.js, Express, and the fs (file system) module. This example uses a JSON file to store the TODOs. Keep in mind that using a database like MongoDB is typically recommended for a production environment.

1. Initialize your project:

    mkdir todo-backend
    cd todo-backend
    npm init -y
    npm install express body-parser
   

2. Create a file namedserver.js:

    const express = require('express');
    const bodyParser = require('body-parser');
    const fs = require('fs/promises');
    const path = require('path');
   
    const app = express();
    const PORT = 3000;
   
    app.use(bodyParser.json());
   
    // Set up routes
    app.get('/todos', async (req, res) => {
      try {
        const data = await fs.readFile(path.join(__dirname, 'todos.json'));
        const todos = JSON.parse(data);
        res.json(todos);
      } catch (error) {
        res.status(500).json({ error: 'Internal Server Error' });
      }
    });
   
    app.post('/todos', async (req, res) => {
      try {
        const data = await fs.readFile(path.join(__dirname, 'todos.json'));
        const todos = JSON.parse(data);
        const newTodo = { id: Date.now(), text: req.body.text, completed: false };
        todos.push(newTodo);
        await fs.writeFile(path.join(__dirname, 'todos.json'), JSON.stringify(todos, null, 2));
        res.json(newTodo);
      } catch (error) {
        res.status(500).json({ error: 'Internal Server Error' });
      }
    });
   
    app.put('/todos/:id', async (req, res) => {
      try {
        const data = await fs.readFile(path.join(__dirname, 'todos.json'));
        let todos = JSON.parse(data);
        const id = parseInt(req.params.id);
        const updatedTodoIndex = todos.findIndex(todo => todo.id === id);
   
        if (updatedTodoIndex === -1) {
          return res.status(404).json({ error: 'Todo not found' });
        }
   
        todos[updatedTodoIndex] = { ...todos[updatedTodoIndex], ...req.body };
        await fs.writeFile(path.join(__dirname, 'todos.json'), JSON.stringify(todos, null, 2));
        res.json(todos[updatedTodoIndex]);
      } catch (error) {
        res.status(500).json({ error: 'Internal Server Error' });
      }
    });
   
    app.delete('/todos/:id', async (req, res) => {
      try {
        const data = await fs.readFile(path.join(__dirname, 'todos.json'));
        let todos = JSON.parse(data);
        const id = parseInt(req.params.id);
        todos = todos.filter(todo => todo.id !== id);
        await fs.writeFile(path.join(__dirname, 'todos.json'), JSON.stringify(todos, null, 2));
        res.json({ message: 'Todo deleted successfully' });
      } catch (error) {
        res.status(500).json({ error: 'Internal Server Error' });
      }
    });
   
    app.listen(PORT, () => {
      console.log(`Server is running on port ${PORT}`);
    });
   

3. Create atodos.json file:

   Create a todos.json file in the same directory as your server.js. This file will initially be an empty array: [].

    []
   

4. Run your server:

    node server.js
   

Now you have a simple TODO app backend with CRUD operations using Node.js, Express, and the fs module. Keep in mind that this is a basic example, and in a production environment, you'd typically use a database for better scalability and reliability.