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)


If we use mutable objects that are shared among multiple components, Angular cannot know about when those components can be affected. A component can affect any other components in the system. That is why, by default, Angular does not make any assumptions about what a component depends upon. So it has be conservative and check every template of every component on every browser event. Since the framework has to do it for every component, it might become a performance problem even though the change detection in the new versions of Angular got way faster.

If our model application state uses immutable objects, like in the preceding example, we can tell a lot more about when the talk component can change. The component can change if and only if any of its inputs changes. And we can communicate it to Angular by setting the change detection strategy to OnPush.

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