Error in MySQL library for Node.js

The net module required and used in the MySQL node module is a core part of Node.js itself. The error you’re getting about Net.createConnection not being a function means it’s coming up as an empty object and the error is related to one of your comment to the question:

I am testing my code within a browser.

You must run this particular module on Node.js only, you can’t run it in a web browser.

One could think a possibility would be to run your code through a packer like browserify or webpack so you can easily require('mysql') in your browser but it won’t work. The net module which is a core dependency of the mysql module will be transformed into an empty object {}.
That’s not a bug, it’s how it’s supposed to work. Browsers don’t have generic tcp implementations so it can’t be emulated. The empty object is intended to prevent require('net') from failing on modules that otherwise work in the browser.

To avoid this error, you need to run this code in a pure Node.js environment, not in a browser. A simple server could serve this purpose since this code in your client in a browser can’t work and would add a security hole as everything client-side is manipulative and as such not secure. You don’t want to expose your database on the client-side but only consumes it.

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