Mastering JavaScript Functional Programming - Second Edition

Basic concepts and terms

Using FRP requires getting used to several new terms, so let's begin with a short glossary:

• Observable: This represents a stream of (present or future) values and can be connected to an observer. You can create observables from practically anything, but the most common case is from events. By convention, observable variable names end with $; see https://angular.io/guide/rx-library#naming-conventions.
• Observer: This is either a callback that is executed whenever the observable it's subscribed to produce a new value or an object with three methods: next(), error(), and complete(), which will be called by the observable when a value is available, when there's an error, and when the stream is ended respectively.
• Operators ...