Using Observables to Transform Data

One of the most intriguing, somewhat difficult, but fun parts of JavaScript programming is based around the handling of events. Whenever we issue an asynchronous call, we are essentially waiting for an event to occur that will trigger our callback processing. We generally have no control over how long an asynchronous call might take, especially if this call is to a server somewhere via an API call. In a similar vein, when running a JavaScript application on the browser, we are often waiting for a user to interact with our software and generate an event via a button click, or a keypress. Again, we have no control over how long the user will take to click that button, or indeed the order in which buttons could be clicked. Think of a small child playing with a keyboard. They may hit a group of buttons at the same time by using their fist to smash the keyboard, or they may hit a completely random combination of keys. It is up to our software to handle...