Build Reactive Websites with RxJS

Introducing Rx Concepts

First, we need to figure out where observables stand in the greater context of JavaScript land. This is a variable:

let myVar = 42;

As you probably know, a variable contains a single value and that value can be used immediately after declaration. Variables are pretty simple. On the other hand, we have arrays:

let myArr = [42, 'hello world', NaN];

This array represents a collection of values. Like the humble variable, an array also contains its data at the moment of creation. If all of programming just used these two concepts, life would be pretty easy. Everything needed to run a program would be immediately available when the program started. Unfortunately, there are times when the data the program needs isn’t ...