Modules have become a major part of the JavaScript ecosystem. They allow us to split our JavaScript programs up into separate smaller parts, called modules, that can be imported when needed. In this article, we will have a look at how we can include local modules in our Node.js app, and then see how that differentiates from including them in Firebase Cloud Functions. Before we continue, do note that this is not an introduction to Firebase. A basic understanding of Firebase and JavaScript is required before reading on about the examples that I'm about to explain.

We all know that in JavaScript there is no event that fires when a value of a variable changes. But by defining getters and setters in the object this is now possible. First, define a new property on an object with "Object.defineProperty" method. As a first argument, we pass the object on which to define the property. If the object is defined in the global scope, "this" will refer to the window object. In the second argument, we will define the name of the property. In our case, we define a property with name "name". The third argument is the descriptor for the property being defined.

Firebase as a platform that offers a wide range of services to developers to build, improve, and grow their apps with little or almost no effort. This includes services like authentication, databases, analytics, file storage, push messaging and more. When it comes to user authentication, Firebase provides an Authentication service that allows for codes to be written in order for users to be logged into an app right from the client side, and limit user access to resources in other Firebase products. This is fairly simple to use without the need to implement any backend solution. Firebase also provides an Admin SDK that allows developers to build a custom backend if required.