How to Fix: ExpressJS - throw er Unhandled error event
The application is trying to listen on a port that is already in use.
📋 Table of Contents
The 'throw er Unhandled error event' issue in ExpressJS is often caused by an uncaught exception or an error that occurs during the application's execution. In this scenario, the error 'listen EADDRINUSE' indicates that another process is using the port already.
⚠️ Common Causes
- Another application or process is using the same port.
🔧 Proven Troubleshooting Steps
Method 1: Checking Port Usage
- Step 1: Open a terminal and run the command 'netstat -tlnp | grep
' to check if another process is using the port.
Method 2: Using a Port Scanner
- Step 1: Install the 'portscanner' package by running the command 'npm install portscanner'. Then, run 'portscanner -p
' to scan for open ports.
✨ Wrapping Up
To resolve the issue, ensure that no other process is using the same port. If necessary, modify your ExpressJS application to use a different port or handle the error properly by adding an unhandled rejection handler.
❓ Frequently Asked Questions
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