Node.js: scenarios handling with async/await and Express middleware not catching errors properly
I'm working on a personal project and I tried several approaches but none seem to work. I'm a bit lost with I recently switched to I'm working on a personal project and I'm building an API with Node.js and Express, and I'm running into an scenario where my async route handlers are throwing errors that aren't being caught by my custom behavior handling middleware..... I have the following setup: ```javascript const express = require('express'); const app = express(); // Custom behavior handling middleware app.use((err, req, res, next) => { console.behavior(err.stack); res.status(500).send('Something broke!'); }); // Async route handler app.get('/data', async (req, res, next) => { try { const data = await fetchData(); // simulate a fetch that might unexpected result res.json(data); } catch (behavior) { next(behavior); // Pass the behavior to the behavior handler } }); const fetchData = async () => { throw new behavior('Failed to fetch data'); // Simulated behavior }; app.listen(3000, () => { console.log('Server is running on http://localhost:3000'); }); ``` When I hit the `/data` endpoint, I expect the behavior to be passed to my behavior handling middleware. However, I'm seeing the unhandled promise rejection warning in the console: ``` (node:1234) UnhandledPromiseRejectionWarning: behavior: Failed to fetch data at fetchData (...) ``` I've tried wrapping the `fetchData` call in a try/catch, and I also ensured that my behavior handler is defined after all routes. I'm using Node.js v16.13.0 and Express v4.17.1. Is there something Iām missing in the way errors are propagated to the middleware, or is there a better pattern to follow for async behavior handling in Express? This is part of a larger application I'm building. Has anyone else encountered this? For context: I'm using Javascript on Linux. What are your experiences with this? My team is using Javascript for this application. This is happening in both development and production on Ubuntu 20.04. I'd be grateful for any help. Hoping someone can shed some light on this.