Verify MIME type error you saw 'text/html' usually means the server tried to render a 404 error page instead of serving the JavaScript file. This should be resolved once you ensure that:

1. express.static middleware is set up correctly and is above other route handlers
2. Inside public dir, you should have a js folder, and within it, a file named app.js (public/js/app.js)
3. Make sure that app.use(express.static(pathToPublic)) is placed above any route handlers like the 404 route in your server setup. Otherwise, the 404 route could be intercepting requests to static files.