docs(guide): add Dart intro

closes #460
This commit is contained in:
Tom Ingebretsen 2015-12-05 18:35:03 -07:00 committed by Kathy Walrath
parent a1c5d44468
commit 40312da5b0
19 changed files with 736 additions and 180 deletions

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// #docregion
library developer_guide_intro.backend_service;
import 'package:angular2/angular2.dart';
import 'package:developer_guide_intro/logger_service.dart';
import 'package:developer_guide_intro/hero.dart';
@Injectable()
class BackendService {
final Logger _logger;
List getAll(type) {
// TODO get from the database and return as a promise
if (type == Hero) {
return [
new Hero('Windstorm', power: 'Weather mastery'),
new Hero('Mr. Nice', power: 'Killing them with kindness'),
new Hero('Magneta', power: 'Manipulates metalic objects')
];
}
_logger.error('Cannot get object of this type');
throw new ArgumentError("TODO: put log content here");
}
BackendService(Logger this._logger);
}

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// #docregion
library developer_guide_intro.hero;
class Hero {
static int _nextId = 1;
int id;
String name;
String power;
Hero(this.name, {this.power}) {
id = _nextId++;
}
}

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// #docregion
library developer_guide_intro.hero_detail_component;
import 'package:angular2/angular2.dart';
import 'package:developer_guide_intro/hero.dart';
@Component(selector: 'hero-detail', templateUrl: 'hero_detail_component.html')
class HeroDetailComponent {
@Input()
Type hero = Hero;
}

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<hr>
<h4>{{hero.name}} Detail</h4>
<div>Id: {{hero.id}}</div>
<div>Name:
<!-- #docregion ng-model -->
<input [(ngModel)]="hero.name"></div>
<!-- #enddocregion ng-model -->
<div>Power:<input [(ngModel)]="hero.power">
</div>

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// #docplaster
library developer_guide_intro.hero_list_component;
import 'package:angular2/angular2.dart';
import 'package:developer_guide_intro/hero.dart';
import 'package:developer_guide_intro/hero_detail_component.dart';
import 'package:developer_guide_intro/hero_service.dart';
// #docregion metadata
// #docregion providers
@Component(
// #enddocregion providers
selector: 'hero-list',
templateUrl: 'hero_list_component.html',
directives: const [HeroDetailComponent],
// #docregion providers
providers: const [HeroService])
// #enddocregion providers
// #enddocregion metadata
/*
// #docregion metadata, providers
class HeroListComponent { ... }
// #enddocregion metadata, providers
*/
// #docregion class
class HeroListComponent {
List<Hero> heroes;
Hero selectedHero;
// #docregion ctor
HeroListComponent(HeroService heroService) {
heroes = heroService.getHeroes();
}
// #enddocregion ctor
selectHero(Hero hero) {
selectedHero = hero;
}
}
// #enddocregion class

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<!-- #docregion -->
<h2>Hero List</h2>
<div *ngFor="#hero of heroes" (click)="selectHero(hero)">
{{hero.name}}
</div>
<hero-detail *ngIf="selectedHero != null" [hero]="selectedHero"></hero-detail>

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<!--#docregion binding -->
<div ... >{{hero.name}}</div>
<hero-detail ... [hero]="selectedHero"></hero-detail>
<div ... (click)="selectHero(hero)">...</div>
<!--#enddocregion binding -->
<!--#docregion structural -->
<div *ngFor="#hero of heroes" ...>...</div>
<hero-detail *ngIf="selectedHero != null" ...></hero-detail>
<!--#enddocregion structural -->

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library developer_guide_intro.hero_service;
import 'package:angular2/angular2.dart';
import 'package:developer_guide_intro/hero.dart';
import 'package:developer_guide_intro/backend_service.dart';
import 'package:developer_guide_intro/logger_service.dart';
// #docregion class
@Injectable()
class HeroService {
final BackendService _backendService;
final Logger _logger;
HeroService(Logger this._logger, BackendService this._backendService);
List<Hero> getHeroes() {
List<Hero> heroes = _backendService.getAll(Hero);
_logger.log('Got ${heroes.length} heroes from the server.');
return heroes;
}
}
// #enddocregion class

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// #docregion
library developer_guide_intro.logger_service;
import 'dart:html';
import 'package:angular2/angular2.dart';
/// A service for logging messages of various types.
///
/// We could switch this implementation to use package:logging.
@Injectable()
class Logger {
void log(Object msg) => window.console.log(msg);
void error(Object msg) => window.console.error(msg);
void warn(Object msg) => window.console.warn(msg);
}

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name: developer_guide_intro
description: Developer Guide Intro
version: 0.0.1
dependencies:
angular2: 2.0.0-beta.0
browser: ^0.10.0
transformers:
- angular2:
platform_directives: 'package:angular2/src/common/directives.dart#CORE_DIRECTIVES'
entry_points: web/main.dart

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<!DOCTYPE html>
<html>
<head>
<title>Intro to Angular 2</title>
<script defer src="main.dart" type="application/dart"></script>
<script defer src="packages/browser/dart.js"></script>
</head>
<body>
<hero-list>Loading...</hero-list>
</body>
</html>

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// #docregion
import 'package:angular2/bootstrap.dart';
import 'package:developer_guide_intro/backend_service.dart';
import 'package:developer_guide_intro/hero_service.dart';
import 'package:developer_guide_intro/logger_service.dart';
import 'package:developer_guide_intro/hero_list_component.dart';
main() {
// #docregion bootstrap
bootstrap(HeroListComponent, [BackendService, HeroService, Logger]);
// #enddocregion bootstrap
}

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"guide": {
"icon": "list",
"title": "Step By Step Guide",
"title": "Developers Guide",
"banner": "Angular 2 is currently in Beta."
},

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@ -2,15 +2,15 @@
"_listtype": "ordered",
"index": {
"title": "Step By Step Guide"
"title": "Developers Guide"
},
"cheatsheet": {
"title": "Angular Cheat Sheet"
},
"setup": {
"title": "Getting Started"
"architecture": {
"title": "Architecture Overview"
},
"displaying-data": {

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include ../../../../_includes/_util-fns
:marked
Angular 2 is a framework to help us build client applications in HTML and
either JavaScript or a language (like Dart or TypeScript) that compiles to JavaScript.
Angular 2 for Dart is published as the `angular2` package, which
(like many other Dart packages) is available via the Pub tool.
With Angular, we write applications by composing HTML *templates* with Angularized markup,
writing *component* classes to manage those templates, adding application logic in *services*,
and handing the top root component to Angular's *bootstrapper*.
Angular takes over, presenting our application content in a browser and responding to user interactions
according to the instructions we provided.
figure
img(src="/resources/images/devguide/architecture/airplane.png" alt="Us" align="left" style="width:200px; margin-left:-40px;margin-right:10px" )
:marked
Of course there is more to it than this.
We're cruising at high altitude in this overview.
We're looking for landmarks. We should expect the object below to be fuzzy and obscured by occasional clouds.
Details become more clear and precise when we land in the chapters themselves.
<br clear="all">
:marked
An Angular 2 for Dart application rests on seven main building blocks:
1. [Components](#component)
1. [Templates](#template)
1. [Metadata](#metadata)
1. [Data binding](#data-binding)
1. [Directives](#directive)
1. [Services](#service)
1. [Dependency injection](#dependency-injection)
figure
img(src="/resources/images/devguide/architecture/overview.png" alt="overview" style="margin-left:-40px;" width="700")
:marked
Learn these seven and we're on our way.
.l-main-section
<a id="component"></a>
:marked
## Components
figure
img(src="/resources/images/devguide/architecture/hero-component.png" alt="Component" align="left" style="width:200px; margin-left:-40px;margin-right:10px" )
:marked
A **component** controls a patch of screen real estate that we could call a *view*.
A set of navigation links, a list of heroes, a hero editor ...
they're all views controlled by components.
We define a component's application logic — what it does to support the view — inside a class.
The class interacts with the view through an API of properties and methods.
<a id="component-code"></a>
A `HeroListComponent`, for example, might have a `heroes` property that returns an array of heroes
that it acquired from a service.
It might have a `selectHero()` method that sets a `selectedHero` property when the user clicks to choose a hero from that list.
The component might be a class like this:
+makeExample('architecture/dart/lib/hero_list_component.dart', 'class', 'lib/hero_list_component.dart')
:marked
Angular creates, updates, and destroys components as the user moves through the application.
The developer can take action at each moment in this lifecycle through optional lifecycle hooks.
<!-- PENDING: What was that supposed to link to? -->
.l-sub-section
:marked
We may wonder who is calling the component's constructor? Who provides the service parameter?
For the moment, have faith that Angular will call the constructor and deliver an
appropriate `HeroService` when we need it.
.l-main-section
<a id="template"></a>
:marked
## Templates
figure
img(src="/resources/images/devguide/architecture/template.png" alt="Template" align="left" style="width:200px; margin-left:-40px;margin-right:10px" )
:marked
We define a component's view with its companion **template**. A template is a form of HTML
that tells Angular how to render the component.
A template looks like regular HTML much of the time ... and then it gets a bit strange. Here is a
template for our `HeroListComponent`:
+makeExample('architecture/dart/lib/hero_list_component.html', null, 'lib/hero_list_component.html')
:marked
This template features typical HTML elements like `<h2>` and `<div>`.
But what are `*ngFor`, <code>{&zwnj;{hero.name}}</code>, `(click)`, `[hero]`, and `<hero-detail>`?
They're examples of Angular's template syntax. <!-- TODO: link to template-syntax.html -->
We'll grow accustomed to that syntax and may even learn to love it.
Take a look at the last line,
which has the `<hero-detail>` tag.
That tag adds a custom element representing a component we haven't seen yet,
a `HeroDetailComponent`.
The `HeroDetailComponent` is a *different* component than the `HeroListComponent` we've seen.
The `HeroDetailComponent` (code not shown) presents facts about a particular hero, the
hero that the user selects from the list presented by the the `HeroListComponent`.
The `HeroDetailComponent` is a **child** of the `HeroListComponent`.
figure
img(src="/resources/images/devguide/architecture/component-tree.png" alt="Metadata" align="left" style="width:300px; margin-left:-40px;margin-right:10px" )
:marked
Notice how `<hero-detail>` rests comfortably among native HTML elements.
We can and _will_ mix our custom components with native HTML in the same layouts.
In this manner we'll compose complex component trees to build out our richly featured application.
<br clear="all">
.l-main-section
<a id="metadata"></a>
:marked
## Metadata
figure
img(src="/resources/images/devguide/architecture/metadata.png" alt="Metadata" align="left" style="width:150px; margin-left:-40px;margin-right:10px" )
:marked
<p style="padding-top:10px">Metadata tells Angular how to process a class.</p>
<br clear="all">
:marked
[Looking back at the code](#component-code) for `HeroListComponent`, we see that it's just a class.
There is no evidence of a framework, no "Angular" in it at all.
In fact, it really is *just a class*. It's not a component until we *tell Angular about it*.
We tell Angular that `HeroListComponent` is a component by attaching **metadata** to the class.
In Dart, we attach metadata by using an **annotation**.
Here's some metadata for `HeroListComponent`:
+makeExample('architecture/dart/lib/hero_list_component.dart', 'metadata', 'lib/hero_list_component.dart')
:marked
Here we see the `@Component` annotation, which (no surprise) identifies the class
immediately below it as a component class.
Annotations often have configuration parameters.
The `@Component` annotation takes parameters to provide the
information Angular needs to create and present the component and its view.
Here we see a few of the possible `@Component` parameters:
* `selector`: A CSS selector that tells Angular to create and insert an instance of this component
where it finds a `<hero-list>` tag in *parent* HTML.
For example, if an app's HTML contains `<hero-list></hero-list>`, then
Angular inserts an instance of the `HeroListComponent` view between those tags.
* `templateUrl`: The address of this component's template, which we showed [above](#the-template).
* `directives`: An array of the components or directives that *this* template requires.
We saw in the last line of our template that we expect Angular to insert a `HeroDetailComponent`
in the space indicated by `<hero-detail>` tags.
Angular will do so only if we mention the `HeroDetailComponent` in this `directives` array.
* `providers`: An array of **dependency injection providers** for services that the component requires.
This is one way to tell Angular that our component's constructor requires a `HeroService`
so it can get the list of heroes to display. We'll get to dependency injection later.
figure
img(src="/resources/images/devguide/architecture/template-metadata-component.png" alt="Metadata" align="left" style="height:200px; margin-left:-40px;margin-right:10px" )
:marked
At runtime, Angular discovers the metadata specified by the `@Component`
annotation. That's how Angular learns how to do "the right thing".
The template, metadata, and component together describe the view.
We apply other metadata annotations in a similar fashion to guide Angular behavior.
`@Injectable`, `@Input`, `@Output`, and `@RouterConfig` are a few of the more popular annotations
we'll master as our Angular knowledge grows.
<br clear="all">
:marked
The architectural takeaway is that we must add metadata to our code
so that Angular knows what to do.
.l-main-section
<a id="data-binding"></a>
:marked
## Data binding
Without a framework, we would be responsible for pushing data values into the HTML controls and turning user responses
into actions and value updates. Writing such push/pull logic by hand is tedious, error-prone, and a nightmare to
read as any experienced jQuery programmer can attest.
figure
img(src="/resources/images/devguide/architecture/databinding.png" alt="Data Binding" style="width:220px; float:left; margin-left:-40px;margin-right:20px" )
:marked
Angular supports **data binding**,
a mechanism for coordinating parts of a template with parts of a component.
We add binding markup to the template HTML to tell Angular how to connect both sides.
There are four forms of data binding syntax. Each form has a direction — to the DOM, from the DOM, or in both directions —
as indicated by the arrows in the diagram.
<br clear="all">
:marked
We saw three forms of data binding in our [example](#template) template:
+makeExample('architecture/dart/lib/hero_list_component_1.html', 'binding')(format=".")
:marked
* The <code>{&zwnj;{hero.name}}</code> [interpolation](displaying-data.html#interpolation)
displays the component's `hero.name` property value within the `<div>` tags.
* The `[hero]` property binding <!-- TODO: link to template-syntax.html#property-binding-->
passes the value of `selectedHero` from
the parent `HeroListComponent` to the `hero` property of the child `HeroDetailComponent`.
* The `(click)` [event binding](user-input.html#click) calls the component's `selectHero` method when the user clicks a hero's name.
**Two-way data binding** is an important fourth form
that combines property and event binding in a single notation, using the `ngModel` directive.
We didn't have a two-way binding in the `HeroListComponent` template;
here's an example from the `HeroDetailComponent` template:
+makeExample('architecture/dart/lib/hero_detail_component.html', 'ng-model', 'lib/hero_detail_component.html (excerpt)')(format=".")
:marked
In two-way binding, a data property value flows to the input box from the component as with property binding.
The user's changes also flow back to the component, resetting the property to the latest value,
as with event binding.
Angular processes *all* data bindings once per JavaScript event cycle,
depth-first from the root of the application component tree.
<!-- PENDING: clarify what "depth-first from the root" really means,
or reassure that they'll learn it soon. -->
figure
img(src="/resources/images/devguide/architecture/component-databinding.png" alt="Data Binding" style="float:left; width:300px; margin-left:-40px;margin-right:10px" )
:marked
We don't know all the details yet,
but it's clear from these examples that data binding plays an important role in communication
between a template and its component.
<br clear="all">
figure
img(src="/resources/images/devguide/architecture/parent-child-binding.png" alt="Parent/Child binding" style="float:left; width:300px; margin-left:-40px;margin-right:10px" )
:marked
Data binding is also important for communication between parent and child components.
<br clear="all">
.l-main-section
<a id="directive"></a>
:marked
## Directives
figure
img(src="/resources/images/devguide/architecture/directive.png" alt="Parent child" style="float:left; width:150px; margin-left:-40px;margin-right:10px" )
:marked
Angular templates are *dynamic*. When Angular renders them, it transforms the DOM
according to the instructions given by **directives**.
A directive is a class with directive metadata. In Dart we apply the `@Directive` annotation
to attach metadata to the class.
<br clear="all">
:marked
We already met one form of directive: the component. A component is a *directive-with-a-template*;
a `@Component` annotation is actually a `@Directive` annotation extended with template-oriented features.
.l-sub-section
:marked
While **a component is technically a directive**,
components are so distinctive and central to Angular applications that we chose
to separate components from directives in this architectural overview.
:marked
Two *other* kinds of directives exist: _structural_ and _attribute_ directives.
They tend to appear within an element tag like attributes,
sometimes by name but more often as the target of an assignment or a binding.
**Structural** directives alter layout by adding, removing, and replacing elements in DOM.
Our [example](#template) template uses two built-in structural directives:
+makeExample('architecture/dart/lib/hero_list_component_1.html', 'structural')(format=".")
:marked
* [`*ngFor`](displaying-data.html#ng-for) tells Angular to stamp out one `<div>` per hero in the `heroes` list.
* [`*ngIf`](displaying-data.html#ng-if) includes the `HeroDetail` component only if a selected hero exists.
.l-sub-section
:marked
In Dart, **the only value that is true is the boolean value `true`**; all
other values are false. JavaScript and TypeScript, in contrast, treat values
such as 1 and most non-null objects as true. For this reason, the JavaScript
and TypeScript versions of this app can use just `selectedHero` as the value
of the `*ngIf` expression. The Dart version must use a boolean operator such
as `!=` instead.
:marked
**Attribute** directives alter the appearance or behavior of an existing element.
In templates they look like regular HTML attributes, hence the name.
The `ngModel` directive, which implements two-way data binding, is
an example of an attribute directive. `ngModel` modifies the behavior of
an existing element (typically an `<input>`)
by setting its display value property and responding to change events.
+makeExample('architecture/dart/lib/hero_detail_component.html', 'ng-model')(format=".")
:marked
Angular ships with a small number of other directives that either alter the layout structure
(for example, `ngSwitch`) <!-- TODO: link to template-syntax.html#ng-switch -->
or modify aspects of DOM elements and components
(for example, `ngStyle` and `ngClass`).
<!-- PENDING: link to template-syntax.html#ng-style template-syntax.html#ng-class-->
Of course, we can also write our own directives. Components such as
`HeroListComponent` are one kind of custom directive.
<!-- PENDING: link to where to learn more about other kinds! -->
.l-main-section
<a id="service"></a>
:marked
## Services
figure
img(src="/resources/images/devguide/architecture/service.png" alt="Service" style="float:left; margin-left:-40px;margin-right:10px" )
:marked
_Services_ is a broad category encompassing any value, function, or feature that our application needs.
Almost anything can be a service.
A service is typically a class with a narrow, well-defined purpose. It should do something specific and do it well.
<br clear="all">
:marked
Examples include:
* logging service
* data service
* message bus
* tax calculator
* application configuration
There is nothing specifically _Angular_ about services. Angular itself has no definition of a service.
There is no service base class, and no place to register a service.
Yet services are fundamental to any Angular application. Our components are big consumers of services.
We prefer our component classes lean. Our components don't fetch data from the server,
they don't validate user input, and they don't log directly to console. They delegate such tasks to services.
A component's job is to enable the user experience and nothing more. It mediates between the view (rendered by the template)
and the application logic (which often includes some notion of a _model_).
A good component presents properties and methods for data binding.
It delegates everything nontrivial to services.
Angular doesn't *enforce* these principles.
It won't complain if we write a "kitchen sink" component with 3000 lines.
Angular does help us *follow* these principles by making it easy to factor our
application logic into services and make those services available to components through *dependency injection*.
.l-main-section
<a id="dependency-injection"></a>
:marked
## Dependency injection
figure
img(src="/resources/images/devguide/architecture/dependency-injection.png" alt="Service" style="float:left; width:200px; margin-left:-40px;margin-right:10px" )
:marked
Dependency injection is a way to supply a new instance of a class
with the fully-formed dependencies it requires. Most dependencies are services.
Angular uses dependency injection to provide new components with the services they need.
<br clear="all">
:marked
Angular can tell which services a component needs by looking at the types of its constructor parameters.
For example, the constructor of our `HeroListComponent` needs a `HeroService`:
+makeExample('architecture/dart/lib/hero_list_component.dart', 'ctor', 'lib/hero_list_component.dart (excerpt)')(format='.')
:marked
When Angular creates a component, it first asks an **injector** for
the services that the component requires.
An injector maintains a container of service instances that it has previously created.
If a requested service instance is not in the container, the injector makes one and adds it to the container
before returning the service to Angular.
When all requested services have been resolved and returned,
Angular can call the component's constructor with those services as arguments.
This is what we mean by *dependency injection*.
The process of `HeroService` injection looks a bit like this:
figure
img(src="/resources/images/devguide/architecture/injector-injects.png" alt="Service" )
:marked
If the injector doesn't have a `HeroService`, how does it know how to make one?
In brief, we must have previously registered a **provider** of the `HeroService` with the injector.
A provider is something that can create or return a service, typically the service class itself.
We can register providers at any level of the application component tree.
We often do so at the root when we bootstrap the application so that
the same instance of a service is available everywhere.
+makeExample('architecture/dart/web/main.dart', 'bootstrap', 'web/main.dart (excerpt)')(format='.')
:marked
Alternatively, we might register at a component level:
+makeExample('architecture/dart/lib/hero_list_component.dart', 'providers', 'lib/hero_list_component.dart (excerpt)')(format='.')
:marked
Registering at a component level means we get a new instance of the
service with each new instance of that component.
<!-- We've vastly oversimplified dependency injection for this overview.
The full story is in the [Dependency Injection](dependency-injection.html) chapter. -->
Points to remember about dependency injection:
* Dependency injection is wired into the Angular framework and used everywhere.
* The *injector* is the main mechanism.
* An injector maintains a *container* of service instances that it created.
* An injector can create a new service instance from a *provider*.
* A *provider* is a recipe for creating a service.
* We register *providers* with injectors.
<a id="other-stuff"></a>
.l-main-section
:marked
## Other stuff
We've learned just a bit about the seven main building blocks of an Angular application:
1. [Components](#component)
1. [Templates](#template)
1. [Metadata](#metadata)
1. [Data binding](#data-binding)
1. [Directives](#directive)
1. [Services](#service)
1. [Dependency injection](#dependency-injection)
That's a foundation for everything else in an Angular application,
and it's more than enough to get going.
But it doesn't include everything we'll need or want to know.
Here is a brief, alphabetical list of other important Angular features and services.
Most of them are covered in this Developers Guide (or soon will be).
>**Animations:** A forthcoming animation library makes it easy for developers to animate component behavior
without deep knowledge of animation techniques or CSS.
>**Bootstrap:** A method to configure and launch the root application component.
>**Change detection:** Learn how Angular decides that a component property value has changed and
when to update the screen.
Learn how it uses **zones** to intercept asynchronous activity and run its change detection strategies.
>**Component router:** With the component Router service, users can navigate a multi-screen application
in a familiar web browsing style using URLs.
>**Events:** The DOM raises events. So can components and services. Angular offers mechanisms for
publishing and subscribing to events including an implementation of the [RxJS Observable](https://github.com/zenparsing/es-observable) proposal.
>**[Forms](forms.html):** Support complex data entry scenarios with HTML-based validation and dirty checking.
>**HTTP:** Communicate with a server to get data, save data, and invoke server-side actions with this Angular HTTP client.
>**Lifecycle hooks:** We can tap into key moments in the lifetime of a component, from its creation to its destruction,
by implementing the lifecycle hook interfaces.
>**Pipes:** Services that transform values for display.
We can put pipes in our templates to improve the user experience. Consider
this `currency` pipe expression:
<div style="margin-left:40px">
code-example(language="javascript" linenumbers=".").
price | currency:'USD':true'
</div>
:marked
>It displays a price of "42.33" as `$42.33`.
>**Testing:** Angular provides a
[testing library](https://pub.dartlang.org/packages/angular2_testing)
to run unit tests on our application parts as they interact with the Angular framework.

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@ -60,6 +60,7 @@
All three of these files remain similar in the rest of the examples,
so we'll focus on what changes.
<a id="interpolation"></a>
.l-main-section
h2#section-showing-properties-with-interpolation Showing properties with interpolation
p.
@ -152,6 +153,7 @@
p Reload the app, and you'll now see the seconds updating automatically.
<a id="ng-for"></a>
.l-main-section
h2#Create-an-array Display an iterable using *ng-for
p Moving up from a single value, create a property that's a list of values.
@ -268,6 +270,7 @@
code-example(language="dart").
@Component(selector: 'display', <span class="pnk">viewProviders: const [FriendsService]</span>)
<a id="ng-if"></a>
.l-main-section
h2#Conditionally-displaying-data-with-NgIf Conditionally display data using *ng-if
p.

View File

@ -1,10 +1,93 @@
- var number = 1;
ul.is-plain
for page, slug in public.docs[current.path[1]][current.path[2]].guide._data
include ../../../../_includes/_util-fns
if slug != '_listtype' && slug != 'index'
- var url = "/docs/" + current.path[1] + "/" + current.path[2] + "/" + current.path[3] + "/" + slug + ".html"
- var num = number++
:marked
This Developers Guide is a practical guide to Angular for experienced programmers who
are building client applications in HTML and Dart.
figure
img(src="/resources/images/devguide/intro/people.png" alt="Us" align="left" style="width:200px; margin-left:-40px;margin-right:10px" )
:marked
We are on a journey together to understand how Angular works and, more importantly,
how to make it work for us. We look at our application requirements and we see problems to solve.
<br clear="all">
li
!= partial("../../../../_includes/_hover-card", { icon: "icon-number", number: num, name: page.title, url: url })
* How do we get data onto the screen and handle user interactions?
* How do we organize our code into manageable, cohesive chunks of functionality that work together?
* What are the essential Angular building blocks and how do they help?
* How do we minimize routine, mechanical coding in favor of declarative, higher level constructs without losing control?
This chapter begins the journey.
<a id="how-to-read"></a>
:marked
# How to read this guide
Each chapter of this guide targets an Angular feature,
showing how to use it to solve a programming problem.
All the chapters include code snippets ... snippets we can reuse in our own applications.
Typically, these snippets are excerpts from a sample application that accompanies the chapter.
**All the source files** for each sample app are displayed together at the **end of each chapter.**
<!-- Although a few early chapters are written as tutorials, most later chapters
don't explain how to build the accompanying sample.
These non-tutorial chapters highlight key points in code but generally don't include the entire source. -->
<!-- We don't have to read this guide straight through. -->
<!-- The "[Cheat Sheet](cheatsheet.html)" is a handy map to Angular overall. -->
<!-- A few early chapters are arranged sequentially and best read together to establish a foundation in Angular.
But most chapters stand on their own. We can browse to any of them as our interest or some necessity moves us. -->
Here is a learning path we might follow:
1. First, be familiar with Dart programming and with web concepts such as
the DOM, HTML, and CSS. Dart tutorials such as
[Get Started](https://www.dartlang.org/docs/tutorials/get-started/) and
[Connect Dart & HTML](https://www.dartlang.org/docs/tutorials/connect-dart-html/)
are a great way to start.
1. Follow the [QuickStart](../quickstart), which is the "Hello, World" of Angular 2.
It shows how to set up the libraries and tools needed to write *any* Angular app.
It ends with a "proof of life", a running Angular app.
1. Next, read the Developers Guide chapters in order:
<!-- TODO: adjust this text once we have non-introductory/tutorial chapters -->
1. The rest of this chapter, especially the Architecture overview
1. [Displaying Data](displaying-data.html)
1. [User Input](user-input.html)
1. [Forms](forms.html)
<!-- add dependency injection when it exists -->
<!-- add text about template syntax, once that exists -->
1. Consider hopping over to the [TypeScript docs](/docs/ts/latest/)
since they're currently ahead of the Dart docs. (We're working on that!)
Especially check out the [Tutorial](/docs/ts/latest/tutorial/) and
[Cheat Sheet](/docs/ts/latest/guide/cheatsheet.html), and the guide chapters
[Dependency Injection](/docs/ts/latest/guide/dependency-injection.html)
and [Template Syntax](/docs/ts/latest/guide/template-syntax.html).
<!-- Follow your own star from there, wherever it leads. -->
Don't miss the [Cheat Sheet](cheatsheet.html), a handy map to Angular.
<a id="toh"></a>
.l-main-section
:marked
# Appendix: The Hero Staffing Agency
There's a backstory to the <!-- the "Tour of Heroes" and --> samples in this guide.
The world is full of crises large and small.
Fortunately, courageous heroes are prepared to take on every challenge.
The shadowy Hero Staffing Agency matches crises to heroes.
We are contract developers, hired by the Agency to build an application to manage their operations.
The Agency maintains a stable of heroes with special powers.
Ordinary humans submit crises as job requests. The heroes bid to take the job, and the Agency
assigns each job accordingly.
Our application handles every detail of recruiting, tracking, and job assignment.
For example, the [Forms](forms.html) chapter features a screen for
entering personal information about heroes:
figure.image-display
img(src="/resources/images/devguide/forms/hero-form-1.png" width="400px" alt="Clean Form")

View File

@ -1,168 +0,0 @@
.l-main-section
p.
As long as you already
<a href="https://www.dartlang.org/downloads/">have the Dart SDK</a>,
getting started with Angular 2 is simple:
ol
li Depend on the <b>angular2</b> pub package.
li Create a Dart file that defines (directly or indirectly) a
<b>root component</b> and <b>bootstraps</b> Angular.
li Create an HTML file that uses the root component and points to the Dart file
p.
You can use whichever editor or IDE you like,
or just use the command-line tools that the Dart SDK provides.
See <a href="http://www.dartlang.org/tools/">Dart Tools</a>
for more information.
h2#section-install Depend on angular2
p.
To use Angular2 in your app, include angular2 as a dependency in
your app's <b>pubspec.yaml</b> file. For example:
code-example(language="yaml").
# pubspec.yaml
name: getting_started
description: Getting Started example
version: 0.0.1
dependencies:
angular2: 2.0.0-alpha.45
browser: ^0.10.0
transformers:
- angular2:
entry_points: web/main.dart
p.
Run <b>pub get</b> to download the packages your app depends on.
(<a href="https://www.dartlang.org/tools/">Dart-savvy editors and IDEs</a>
typically run <code>pub get</code> for you.)
.l-main-section
h2#section-set-up-the-starting-component Write the Dart code
p.
Next to your <code>pubspec.yaml</code> file,
create a <code>web</code> subdirectory containing a Dart file
(<code>main.dart</code>).
Edit <code>main.dart</code>, adding a component class (<b>AppComponent</b>),
configuring it to bind to the <code>&lt;my-app&gt;</code> element,
and creating a top-level <code>main()</code> function that calls
Angular's <code>bootstrap()</code> function.
code-example(language="dart" escape="html").
// web/main.dart
import 'package:angular2/angular2.dart';
import 'package:angular2/bootstrap.dart';
@Component(selector: 'my-app')
@View(template: '<h1>My first Angular 2 App</h1>')
class AppComponent {}
main() {
bootstrap(AppComponent);
}
.l-main-section
h2#section-create-an-entry-point Create an HTML file
p.
In the <code>web/</code> directory of your app,
create an HTML file (<code>index.html</code>).
Edit <code>index.html</code> to add a <code>&lt;my-app&gt;</code> element
and call <code>main.dart</code>.
code-example(language="html").
&lt;!-- web/index.html --&gt;
&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;head&gt;
&lt;title&gt;Getting Started&lt;/title&gt;
&lt;link rel=&quot;stylesheet&quot; href=&quot;style.css&quot;&gt;
&lt;script async src=&quot;main.dart&quot; type=&quot;application/dart&quot;&gt;&lt;/script&gt;
&lt;script async src=&quot;packages/browser/dart.js&quot;&gt;&lt;/script&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;my-app&gt;&lt;/my-app&gt;
&lt;/body&gt;
&lt;/html&gt
.l-main-section
h2#section-run-it Run the app!
p.
Now run the app. How you do this depends on your tools.
ul
li.
If you're using <b>WebStorm</b> or <b>IntelliJ IDEA</b>,
right-click <b>web/index.html</b>,
and choose <b>Run 'index.html'</b>.
li.
If you're using the command line and don't have Dartium,
serve the app using <code>pub serve</code>,
and then run it by visiting <b>http://localhost:8080</b> in a browser.
Generating the JavaScript takes a few seconds when you first visit the page,
and the generated JavaScript is currently large.
The generated JavaScript will be smaller once
Angular's transformer becomes available.
p.
You should see something like this:
figure.image-display
img(src='/resources/images/examples/setup-example1.png' alt="Example of Todo App")
.l-main-section
h2#section-explanations Explanations
p This basic Angular app contains the structure for any app you'll build.
.l-sub-section
h3 It's all a tree
p.
You can think of an Angular app as a tree of components.
The root component acts as the top-level container for the rest of your application.
You've named this one <code>AppComponent</code>, but there's
nothing special about the name; you can use whatever makes sense to you.
p.
The root component's job is to give a location in the HTML file where
your application can
render through its element—in this case, <code>&lt;my-app&gt;</code>.
There's nothing special about the HTML filename or the element name;
you can pick whatever you like.
p.
The root component loads the initial template for the application,
which loads other components to perform
whatever functions your application needs—menu bars, views, forms, and so on.
We'll walk through examples of all of
these in the following pages.
.l-sub-section
h3 @Component and @View annotations
p.
A component annotation describes details about the component.
An annotation can be identified by its at-sign (<code>@</code>).
p.
The <code>@Component</code> annotation defines the HTML tag for
the component by specifying the component's CSS selector.
p.
The <code>@View</code> annotation defines the HTML that
represents the component.
The component you wrote uses an inline template,
but you can also have an external template.
To use an external template,
specify a <code>templateUrl</code> property and
give it the path to the HTML file.
p.
Exciting! Not excited yet?
Let's move on to <a href="displaying-data.html">Displaying Data</a>.

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@ -81,6 +81,7 @@
&lt;/li&gt;
&lt;/ul&gt;
<a id="click"></a>
.l-main-section
h2#section-add-todos-to-the-list Add todos to the list via button click
p.