How to Fix TypeError: router.ws is not a function in Express.js with TypeScript and express-ws

---

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---

Understanding the Problem

When trying to create a websocket endpoint in your Express app, you might run into the following error:

[[See Video to Reveal this Text or Code Snippet]]

This issue typically arises when the router does not have access to the ws function that express-ws is supposed to provide. This often stems from incorrectly initializing the express-ws middleware or using the router before the middleware has been properly applied to it.

Example of the Issue

Here’s a snippet of code where the error can occur:

[[See Video to Reveal this Text or Code Snippet]]

In the above code, developers call the ws method on the router before properly setting up the websocket support using express-ws.

Step-by-Step Solution

To solve this issue, we need to ensure that the ws function is available on the router when we're attempting to use it. Here’s how you can do this effectively:

1. Adjust Your Router Definition

Example Implementation

[[See Video to Reveal this Text or Code Snippet]]

2. Update Your Server Entry Point

[[See Video to Reveal this Text or Code Snippet]]

3. Test Your Application

Conclusion

Happy coding!