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)

Change Detection

Two phases

Angular separates updating the application model and reflecting the state of the model in the view into two distinct phases. The developer is responsible for updating the application model. Angular via bindings, by means of change detection, is responsible for reflecting the state of the model in the view. The framework does it automatically on every VM turn.

Event bindings, which can be added using the () syntax, can be used to capture a browser event or component output to execute some function on a component or a directive. So they often trigger the first phase.

Property bindings, which can be added using the [] syntax, should be used only for reflecting the state of the model in the view.

As we have learned, an Angular application consists of nested components, so it will always have a component tree. Let's say for this app it looks as follows:

Next, define the application model...