Book Image

Essential Angular

By : Victor Savkin, Jeff Cross
Book Image

Essential Angular

By: Victor Savkin, Jeff Cross

Overview of this book

Essential Angular is a concise, complete overview of the key aspects of Angular, written by two Angular core contributors. The book covers the framework's mental model, its API, and the design principles behind it. This book is fully up to date with the latest release of Angular. Essential Angular gives you a strong foundation in the core Angular technology. It will help you put all the concepts into the right places so you will have a good understanding of why the framework is the way it is. Read this book after you have toyed around with the framework, but before you embark on writing your first serious Angular application. This book covers concepts such as the differences between Just-In-Time (JIT) and Ahead-Of-Time (AOT) compilation in Angular, alongside NgModules, components and directives. It also goes into detail on Dependency Injection and Change Detection: essential skills for Angular developers to master. The book finishes with a look at testing, and how to integrate different testing methodologies in your Angular code.
Table of Contents (11 chapters)

Reactive Programming in Angular

Reactive programming in the core framework

An Angular application is a reactive system. The user clicks on a button, the application reacts to this event and updates the model. The model gets updated, the application propagates the changes through the component tree.

Angular implements these two arrows very differently. Let's explore why.

Events and state

To understand why Angular uses two very different ways of reactive programming, we need to look at the differences between events and the state.

We often talk about events or event streams when discussing reactivity. Event streams are an important category of reactive objects, but so is state. So let's compare their properties.

Events are discrete and cannot be skipped. Every single event matters, including the order in which the events are emitted. The "most recent event" is not a special thing we care about...