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@ -15,9 +15,9 @@ figure
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* What are the essential Angular building blocks and how do they help?
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* How do we minimize routine, mechanical coding in favor of declarative, higher level constructs without losing control?
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This chapter is an introduction in two parts.
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This chapter begins the journey. It's an introduction to Angular in two parts.
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1. [How to read this guide](#how-to-read)
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2. [An Angular architectural overview](#architecture)
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2. [An architecture overview](#architecture)
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.l-main-section
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<a id="how-to-read"></a>
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@ -77,9 +77,9 @@ figure
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The framework consists of several cooperating libraries, some of them core and some optional.
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We write applications by composing HTML templates with Angularized-markup,
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writing "Component" classes to manage those templates, adding application logic in services,
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and handing the top root component to Angular's bootstrapper.
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We write applications by composing HTML *templates* with Angularized-markup,
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writing *component* classes to manage those templates, adding application logic in *services*,
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and handing the top root component to Angular's *bootstrapper*.
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Angular takes over, presenting our application content in a browser and responding to user interactions
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according to the instructions we provided.
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@ -88,9 +88,12 @@ figure
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img(src="/resources/images/devguide/intro/airplane.png" alt="Us" align="left" style="width:200px; margin-left:-40px;margin-right:10px" )
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:marked
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Of course there is more to it than this.
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We're cruising at high altitude in this chapter.
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We're looking for landmarks. We should expect the details to be fuzzy and obscured by occasional clouds.
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We're cruising at high altitude in this overview.
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We're looking for landmarks. We should expect the object below to be fuzzy and obscured by occasional clouds.
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Details become more clear and precise when we land in the chapters themselves.
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<br clear="all">
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:marked
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An Angular 2 application rests on seven main building blocks:
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1. [Component](#component)
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1. [Template](#template)
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@ -112,11 +115,11 @@ figure
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figure
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img(src="/resources/images/devguide/intro/hero-component.png" alt="Component" align="left" style="width:200px; margin-left:-40px;margin-right:10px" )
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:marked
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A **Component** controls a patch of screen real estate that we could call a "view".
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A **Component** controls a patch of screen real estate that we could call a *view*.
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The shell at the application root with navigation links, that list of heroes, the hero editor ...
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they're all views controlled by Components.
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We define a Component's "application logic" - what it does to support the view - inside a class.
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We define a Component's application logic - what it does to support the view - inside a class.
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The class interacts with the view through an API of properties and methods.
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<a id="component-code"></a>
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@ -131,9 +134,11 @@ figure
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The developer can take action at each moment in this lifecycle through optional [Lifecycle Hooks](#).
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.l-sub-section
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:marked
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Our example shows the service arriving via the class constructor.
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Who calls that constructor? Who provides the service?
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For the moment, have faith that Angular is going to deliver an
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We're not showing those hooks in this example
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but we are making a mental note to find out about them later.
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We may wonder who is calling that constructor? Who provides the service parameter?
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For the moment, have faith that Angular will call the constructor and deliver an
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appropriate `HeroService` when we need it.
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.l-main-section
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@ -143,11 +148,11 @@ figure
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figure
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img(src="/resources/images/devguide/intro/template.png" alt="Template" align="left" style="width:200px; margin-left:-40px;margin-right:10px" )
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:marked
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We define a Component's view with its companion **Template**. A template is a form of HTML
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We define a Component's view with its companion **template**. A template is a form of HTML
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that tells Angular how to render the Component.
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A template looks like regular HTML much of the time ... and then it gets a bit strange. Here is a
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template for our `HeroList` Component
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template for our `HeroList` component
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+makeExample('intro/ts/src/app/hero-list.component.html')
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:marked
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We recognize `<h2>` and `<div>`.
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@ -272,7 +277,8 @@ figure
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**Two-way data binding** is an important fourth form
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that combines property and event binding in a single notation using the `ng-model` directive.
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We didn't have a two-way binding in the `HeroListComponent` template; here's an example from a different template:
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We didn't have a two-way binding in the `HeroListComponent` template;
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here's an example from the `HeroDetailComponent` template (not shown):
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+makeExample('intro/ts/src/app/hero-detail.component.html', 'ng-model')(format=".")
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:marked
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@ -285,7 +291,7 @@ figure
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figure
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img(src="/resources/images/devguide/intro/component-databinding.png" alt="Data Binding" style="float:left; width:300px; margin-left:-40px;margin-right:10px" )
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:marked
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We don't know all the details yet
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We don't know all the details yet
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but it's clear from these examples that data binding plays an important role in communication
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between a template and its component ...
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<br clear="all">
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@ -303,7 +309,7 @@ figure
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img(src="/resources/images/devguide/intro/directive.png" alt="Parent child" style="float:left; width:150px; margin-left:-40px;margin-right:10px" )
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:marked
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Our Angular templates are *dynamic*. When Angular renders them, it transforms the DOM
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according to the instructions given by a **Directive**.
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according to the instructions given by a **directive**.
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A directive is a class with directive metadata. In TypeScript we'd apply the `@Directive` decorator
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to attach metadata to the class.
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@ -315,7 +321,7 @@ figure
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.l-sub-section
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:marked
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While the **component is technically a directive**,
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it is so distictive and central to Angular applications that we chose
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it is so distinctive and central to Angular applications that we chose
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to separate the component from the directive in our architectural overview.
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:marked
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There are two *other* kinds of directives as well that we call "structural" and "attribute" directives.
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