What is Node?

Node is an environment in which you can run JavaScript code "Outside the web browser". Node be like – "Hey y'all, you give your JS code to me and I'll run it 😎". It uses Google's V8 Engine to convert the JavaScript code to Machine Code.

Since Node runs JavaScript code outside the web browser, this means that it doesn't have access to certain features that are only available in the browser, like the DOM or the window object or even the localStorage.

This means that at any point in your code, you can't type in document.querySelector() or alert() as these will produce errors (This is what is shown in the below image).

Remember: Node is meant for server-side programming, while those browser features are meant for client-side programming.