Express Async Error Handling: express-async-errors vs express-async-handler

MVC-Style Implementation with express-async-handler

For larger applications, you might prefer an MVC structure. Here's how that would look with express-async-handler:

// controllers/todoController.js
const Todo = require('../models/Todo');
const asyncHandler = require('express-async-handler');

// Controller methods
const getTodos = asyncHandler(async (req, res) => {
  const todos = await Todo.find({});
  res.json(todos);
});

const getTodoById = asyncHandler(async (req, res) => {
  const todo = await Todo.findById(req.params.id);
  if (!todo) {
    res.status(404);
    throw new Error('Todo not found');
  }
  res.json(todo);
});

const createTodo = asyncHandler(async (req, res) => {
  const todo = await Todo.create(req.body);
  res.status(201).json(todo);
});

const updateTodo = asyncHandler(async (req, res) => {
  const todo = await Todo.findByIdAndUpdate(
    req.params.id,
    req.body,
    { new: true, runValidators: true }
  );
  if (!todo) {
    res.status(404);
    throw new Error('Todo not found');
  }
  res.json(todo);
});

const deleteTodo = asyncHandler(async (req, res) => {
  const todo = await Todo.findByIdAndDelete(req.params.id);
  if (!todo) {
    res.status(404);
    throw new Error('Todo not found');
  }
  res.json({ message: 'Todo removed' });
});

module.exports = {
  getTodos,
  getTodoById,
  createTodo,
  updateTodo,
  deleteTodo
};

// routes/todoRoutes.js
const express = require('express');
const router = express.Router();
const {
  getTodos,
  getTodoById,
  createTodo,
  updateTodo,
  deleteTodo
} = require('../controllers/todoController');

router.route('/').get(getTodos).post(createTodo);
router.route('/:id').get(getTodoById).put(updateTodo).delete(deleteTodo);

module.exports = router;

// app.js
const express = require('express');
const mongoose = require('mongoose');
const todoRoutes = require('./routes/todoRoutes');

mongoose.connect('mongodb://localhost/todo-app');

const app = express();
app.use(express.json());

// Mount routes
app.use('/todos', todoRoutes);

// Error handler
app.use((err, req, res, next) => {
  const statusCode = res.statusCode === 200 ? 500 : res.statusCode;
  res.status(statusCode).json({
    message: err.message,
    stack: process.env.NODE_ENV === 'production' ? '🥞' : err.stack
  });
});

app.listen(3000, () => console.log('Server running on port 3000'));

This structure separates concerns nicely and makes your application more maintainable as it grows.