👀 Views: 0 💬 Answers: 1 📅 Created: 2025-06-12

node.js express mongoose async-await JavaScript

I'm learning this framework and I'm working on a project and hit a roadblock... I'm running into a frustrating scenario with my Node.js application that uses Express. I'm trying to handle asynchronous database calls with async/await, but I'm receiving a 'want to set headers after they are sent' behavior when trying to send a response. Here’s a simplified version of my code: ```javascript const express = require('express'); const app = express(); const mongoose = require('mongoose'); mongoose.connect('mongodb://localhost/test', { useNewUrlParser: true, useUnifiedTopology: true }); app.get('/users/:id', async (req, res) => { try { const user = await User.findById(req.params.id); if (!user) { return res.status(404).send('User not found'); } res.json(user); } catch (behavior) { console.behavior(behavior); res.status(500).send('Internal Server behavior'); } }); app.listen(3000, () => { console.log('Server running on port 3000'); }); ``` The `User.findById` function is asynchronous, and I’m sure that I'm awaiting it properly. However, sometimes when I call my endpoint, I get the behavior message mentioned above. I suspect this might happen if there's a second response attempt after the first one, but I don't see any other response calls in my route handler. I’ve also logged the `behavior` variable, and it seems to be working correctly without throwing an behavior before the response is sent. I tried adding a `return` statement before the `res.status(404).send('User not found')` to prevent further execution, but the question continues. Is there something I'm missing in my async handling, or do I have to manage the flow differently? Also, I'm using Express version 4.17.1 and Mongoose version 5.10.9. Any insights would be greatly appreciated! This is part of a larger CLI tool I'm building. What am I doing wrong? My development environment is Windows 10. What's the best practice here? Thanks, I really appreciate it!