diff --git a/public/docs/_examples/displaying-data/dart/lib/app_component.dart b/public/docs/_examples/displaying-data/dart/lib/app_component.dart index 25402e3e3b..5f64cef0d2 100644 --- a/public/docs/_examples/displaying-data/dart/lib/app_component.dart +++ b/public/docs/_examples/displaying-data/dart/lib/app_component.dart @@ -3,30 +3,28 @@ import 'package:angular2/core.dart'; import 'hero.dart'; -final List _heroes = [ - new Hero(1, 'Windstorm'), - new Hero(13, 'Bombasto'), - new Hero(15, 'Magneta'), - new Hero(20, 'Tornado') -]; - @Component( selector: 'my-app', template: ''' -

{{title}}

-

My favorite hero is: {{myHero.name}}

-

Heroes:

- -// #docregion message -

There are many heroes!

-// #enddocregion message -''') +

{{title}}

+

My favorite hero is: {{myHero.name}}

+

Heroes:

+ + // #docregion message +

There are many heroes!

+ // #enddocregion message + ''') class AppComponent { String title = 'Tour of Heroes'; - List heroes = _heroes; - Hero myHero = _heroes[0]; + List heroes = [ + new Hero(1, 'Windstorm'), + new Hero(13, 'Bombasto'), + new Hero(15, 'Magneta'), + new Hero(20, 'Tornado') + ]; + Hero get myHero => heroes.first; } diff --git a/public/docs/_examples/displaying-data/dart/lib/app_component_1.dart b/public/docs/_examples/displaying-data/dart/lib/app_component_1.dart index 20f946fcc5..93a4e5a5a9 100644 --- a/public/docs/_examples/displaying-data/dart/lib/app_component_1.dart +++ b/public/docs/_examples/displaying-data/dart/lib/app_component_1.dart @@ -3,11 +3,12 @@ import 'package:angular2/core.dart'; @Component( selector: 'my-app', -// #docregion template + // #docregion template template: ''' -

{{title}}

-

My favorite hero is: {{myHero}}

''' -// #enddocregion template +

{{title}}

+

My favorite hero is: {{myHero}}

+ ''' + // #enddocregion template ) class AppComponent { String title = 'Tour of Heroes'; diff --git a/public/docs/_examples/displaying-data/dart/lib/app_component_2.dart b/public/docs/_examples/displaying-data/dart/lib/app_component_2.dart index 3d64fd0c02..b28e013dec 100644 --- a/public/docs/_examples/displaying-data/dart/lib/app_component_2.dart +++ b/public/docs/_examples/displaying-data/dart/lib/app_component_2.dart @@ -1,36 +1,26 @@ // #docregion import 'package:angular2/core.dart'; -// #docregion mock-heroes -const List _heroes = const [ - 'Windstorm', - 'Bombasto', - 'Magneta', - 'Tornado' -]; -// #enddocregion mock-heroes - @Component( selector: 'my-app', -// #docregion template + // #docregion template template: ''' -

{{title}}

-

My favorite hero is: {{myHero}}

-

Heroes:

-
    -// #docregion li-repeater -
  • - {{ hero }} -
  • -// #enddocregion li-repeater -
''' -// #enddocregion template +

{{title}}

+

My favorite hero is: {{myHero}}

+

Heroes:

+
    + // #docregion li +
  • + {{ hero }} +
  • + // #enddocregion li +
+ ''' + // #enddocregion template ) -// #docregion mock-heroes +// #docregion class class AppComponent { String title = 'Tour of Heroes'; - List heroes = _heroes; - String myHero = _heroes[0]; + List heroes = ['Windstorm', 'Bombasto', 'Magneta', 'Tornado']; + String get myHero => heroes.first; } -// #enddocregion mock-heroes -// #enddocregion diff --git a/public/docs/_examples/displaying-data/dart/lib/app_component_3.dart b/public/docs/_examples/displaying-data/dart/lib/app_component_3.dart index 51d2827a2a..35e3e94f77 100644 --- a/public/docs/_examples/displaying-data/dart/lib/app_component_3.dart +++ b/public/docs/_examples/displaying-data/dart/lib/app_component_3.dart @@ -1,35 +1,34 @@ // #docregion import 'package:angular2/core.dart'; -// #docregion heroes +// #docregion import import 'hero.dart'; - -final List _heroes = [ - new Hero(1, 'Windstorm'), - new Hero(13, 'Bombasto'), - new Hero(15, 'Magneta'), - new Hero(20, 'Tornado') -]; -// #enddocregion heroes +// #enddocregion import @Component( selector: 'my-app', -// #docregion template + // #docregion template template: ''' -

{{title}}

-

My favorite hero is: {{myHero.name}}

-

Heroes:

-
    -
  • - {{ hero.name }} -
  • -
''' -// #enddocregion template +

{{title}}

+

My favorite hero is: {{myHero.name}}

+

Heroes:

+
    +
  • + {{ hero.name }} +
  • +
+ ''' + // #enddocregion template ) -// #docregion heroes +// #docregion class class AppComponent { String title = 'Tour of Heroes'; - List heroes = _heroes; - Hero myHero = _heroes[0]; + // #docregion heroes + List heroes = [ + new Hero(1, 'Windstorm'), + new Hero(13, 'Bombasto'), + new Hero(15, 'Magneta'), + new Hero(20, 'Tornado') + ]; + Hero get myHero => heroes.first; + // #enddocregion heroes } -// #enddocregion heroes -// #enddocregion diff --git a/public/docs/_examples/displaying-data/dart/lib/hero.dart b/public/docs/_examples/displaying-data/dart/lib/hero.dart index 6542e4f4ca..65d712ee93 100644 --- a/public/docs/_examples/displaying-data/dart/lib/hero.dart +++ b/public/docs/_examples/displaying-data/dart/lib/hero.dart @@ -1,9 +1,9 @@ // #docregion class Hero { - int id; + final int id; String name; Hero(this.id, this.name); + String toString() => '$id: $name'; } -// #enddocregion diff --git a/public/docs/_examples/displaying-data/dart/pubspec.yaml b/public/docs/_examples/displaying-data/dart/pubspec.yaml index eb112ebb45..2ca27306c6 100644 --- a/public/docs/_examples/displaying-data/dart/pubspec.yaml +++ b/public/docs/_examples/displaying-data/dart/pubspec.yaml @@ -1,6 +1,6 @@ # #docregion name: displaying_data -description: Displaying Data Example +description: Displaying Data version: 0.0.1 environment: sdk: '>=1.13.0 <2.0.0' diff --git a/public/docs/_examples/displaying-data/dart/web/index.html b/public/docs/_examples/displaying-data/dart/web/index.html index 6585d21511..e9b9c097a1 100644 --- a/public/docs/_examples/displaying-data/dart/web/index.html +++ b/public/docs/_examples/displaying-data/dart/web/index.html @@ -3,13 +3,14 @@ Displaying Data - + + + - Loading... - + diff --git a/public/docs/_examples/displaying-data/dart/web/main.dart b/public/docs/_examples/displaying-data/dart/web/main.dart index 6a3620979c..f640544559 100644 --- a/public/docs/_examples/displaying-data/dart/web/main.dart +++ b/public/docs/_examples/displaying-data/dart/web/main.dart @@ -9,7 +9,7 @@ import 'package:angular2/platform/browser.dart'; // #docregion final import 'package:displaying_data/app_component.dart'; -main() { +void main() { // #enddocregion final // pick one // bootstrap(v1.AppComponent); diff --git a/public/docs/_examples/displaying-data/ts/app/app-ctor.component.ts b/public/docs/_examples/displaying-data/ts/app/app-ctor.component.ts index d9b816e558..b275baa8e6 100644 --- a/public/docs/_examples/displaying-data/ts/app/app-ctor.component.ts +++ b/public/docs/_examples/displaying-data/ts/app/app-ctor.component.ts @@ -7,7 +7,7 @@ import { Component } from '@angular/core';

My favorite hero is: {{myHero}}

` }) -// #docregion app-ctor +// #docregion class export class AppCtorComponent { title: string; myHero: string; @@ -17,4 +17,3 @@ export class AppCtorComponent { this.myHero = 'Windstorm'; } } -// #enddocregion app-ctor diff --git a/public/docs/_examples/displaying-data/ts/app/app.component.2.ts b/public/docs/_examples/displaying-data/ts/app/app.component.2.ts index 506215b36e..da7a653973 100644 --- a/public/docs/_examples/displaying-data/ts/app/app.component.2.ts +++ b/public/docs/_examples/displaying-data/ts/app/app.component.2.ts @@ -9,20 +9,18 @@ import { Component } from '@angular/core';

My favorite hero is: {{myHero}}

Heroes:

    - // #docregion li-repeater + // #docregion li
  • {{ hero }}
  • - // #enddocregion li-repeater + // #enddocregion li
` // #enddocregion template }) -// #docregion mock-heroes +// #docregion class export class AppComponent { title = 'Tour of Heroes'; heroes = ['Windstorm', 'Bombasto', 'Magneta', 'Tornado']; myHero = this.heroes[0]; } -// #enddocregion mock-heroes -// #enddocregion diff --git a/public/docs/_examples/displaying-data/ts/app/app.component.3.ts b/public/docs/_examples/displaying-data/ts/app/app.component.3.ts index 8ea79cce53..0705176292 100644 --- a/public/docs/_examples/displaying-data/ts/app/app.component.3.ts +++ b/public/docs/_examples/displaying-data/ts/app/app.component.3.ts @@ -1,8 +1,8 @@ // #docregion import { Component } from '@angular/core'; -// #docregion import-hero +// #docregion import import { Hero } from './hero'; -// #enddocregion import-hero +// #enddocregion import @Component({ selector: 'my-app', @@ -32,5 +32,3 @@ export class AppComponent { myHero = this.heroes[0]; // #enddocregion heroes } -// #enddocregion class -// #enddocregion diff --git a/public/docs/_examples/displaying-data/ts/app/app.component.ts b/public/docs/_examples/displaying-data/ts/app/app.component.ts index 1ba40c62c9..40c90e2d62 100644 --- a/public/docs/_examples/displaying-data/ts/app/app.component.ts +++ b/public/docs/_examples/displaying-data/ts/app/app.component.ts @@ -1,8 +1,6 @@ // #docplaster // #docregion final -// #docregion imports import { Component } from '@angular/core'; -// #enddocregion imports import { Hero } from './hero'; @Component({ @@ -17,12 +15,10 @@ import { Hero } from './hero'; // #docregion message -

There are many heroes!

+

There are many heroes!

// #enddocregion message ` }) - export class AppComponent { title = 'Tour of Heroes'; heroes = [ diff --git a/public/docs/_examples/displaying-data/ts/app/hero.ts b/public/docs/_examples/displaying-data/ts/app/hero.ts index e6b3745186..f89d26ad63 100644 --- a/public/docs/_examples/displaying-data/ts/app/hero.ts +++ b/public/docs/_examples/displaying-data/ts/app/hero.ts @@ -1,9 +1,9 @@ // #docregion export class Hero { constructor( - // #docregion id-parameter + // #docregion id public id: number, - // #enddocregion id-parameter + // #enddocregion id public name: string) { } } // #enddocregion diff --git a/public/docs/_examples/displaying-data/ts/index.html b/public/docs/_examples/displaying-data/ts/index.html index e74be1c5de..d9e9291661 100644 --- a/public/docs/_examples/displaying-data/ts/index.html +++ b/public/docs/_examples/displaying-data/ts/index.html @@ -19,10 +19,10 @@ - + loading... - + diff --git a/public/docs/dart/latest/_quickstart_repo.jade b/public/docs/dart/latest/_quickstart_repo.jade new file mode 100644 index 0000000000..e72fbfacf2 --- /dev/null +++ b/public/docs/dart/latest/_quickstart_repo.jade @@ -0,0 +1,4 @@ +.l-sub-section + :marked + Alternatively, begin with a + [download of the QuickStart source](https://github.com/angular-examples/quickstart/archive/master.zip). diff --git a/public/docs/dart/latest/guide/displaying-data.jade b/public/docs/dart/latest/guide/displaying-data.jade index 6e8b96f3c3..9207073069 100644 --- a/public/docs/dart/latest/guide/displaying-data.jade +++ b/public/docs/dart/latest/guide/displaying-data.jade @@ -1,257 +1,24 @@ -include ../_util-fns +extends ../../../ts/latest/guide/displaying-data.jade -:marked - We typically display data in Angular by binding controls in an HTML template - to properties of an Angular component. +block includes + include ../_util-fns + - var _iterableUrl = 'https://api.dartlang.org/stable/dart-core/Iterable-class.html'; + - var _boolean = 'boolean'; - In this chapter, we'll create a component with a list of heroes. Each hero has a name. - We'll display the list of hero names and - conditionally show a selected hero in a detail area below the list. +block quickstart-repo + //- Must have this block so that Jade picks up the Dart include. + include ../_quickstart_repo - The final UI looks like this: - -figure.image-display - img(src="/resources/images/devguide/displaying-data/final.png" alt="Final UI") - - - -.l-main-section -:marked - ## Showing component properties with interpolation - The easiest way to display a component property - is to bind the property name through interpolation. - With interpolation, we put the property name in the view template, enclosed in double curly braces: `{{myHero}}`. - - Let's build a small illustrative example together. - - - Create a new project folder (`displaying`) and create 3 files: - `pubspec.yaml`, `web/index.html`, and `web/main.dart`. - Put these contents in the files: - -- var stylePattern = [{ otl: /(platform_directives.*$)/gm }, null, null]; -+makeTabs('displaying-data/dart/pubspec.yaml, displaying-data/dart/web/index.html, displaying-data/dart/web/main.dart', ',,final', 'pubspec.yaml, web/index.html, web/main.dart', stylePattern) - -:marked - All of this code should look familiar from the - [QuickStart](../quickstart.html), - except for the `platform_directives` entry in `pubspec.yaml` - and the imports in `main.dart`. - - In `pubspec.yaml`, the `platform_directives` entry lets us use - core directives, such as the `ngFor` directive that we'll soon add to our app. - - In `main.dart`, importing `app_component.dart` lets us implement part - of the app in a different Dart file. The QuickStart version of `main.dart` - imported `core.dart`, but we don't need that import here because - this version of `main.dart` is so basic: it only bootstraps the app, - and doesn't implement any components or other injectable types. - - So that the code can run, - let's create a stub for the `` component. - - Create a new directory called `lib`. - In it, put a file called `app_component.dart` - with the following code: - -+makeExample('displaying-data/dart/lib/app_component_1.dart', null, 'lib/app_component.dart') - -:marked - We defined a component with two properties: `title` and `myHero`. - The template displays the two component properties using double curly brace - interpolation: - -+makeExample('displaying-data/dart/lib/app_component_1.dart', 'template')(format=".") - -:marked - Angular automatically pulls the value of the `title` and `myHero` properties from the component and - inserts those values into the browser. Angular updates the display - when these properties change. - - -.l-sub-section - :marked - More precisely, the redisplay occurs after some kind of asynchronous event related to - the view such as a keystroke, a timer completion, or an async `XHR` response. - We don't have those in this sample. - But then the properties aren't changing on their own either. For the moment we must operate on faith. -:marked - Notice that we haven't called **new** to create an instance of the `AppComponent` class. - Angular is creating an instance for us. How? - - Notice the CSS `selector` in the `@Component` decorator that specifies an element named "my-app". - Remember back in QuickStart that we added the `` element to the body of our `index.html` file: -+makeExample('displaying-data/dart/web/index.html', 'my-app')(format=".") - - -:marked - When we bootstrap with the `AppComponent` class (in `main.dart`), Angular looks for a `` - in the `index.html`, finds it, instantiates an instance of `AppComponent`, and renders it - inside the `` tag. - - Try running the app. It should display the title and hero name: -figure.image-display - img(src="/resources/images/devguide/displaying-data/title-and-hero.png" alt="Title and Hero") -// TODO: Here the TS version says "Let's review some of the choices we made and consider alternatives." However, it's unclear where this review ends. Clarify the structure in the TS, and make sure this is the best place for the Dart version of this section. - -#performance.l-sub-section - :marked - ### Template inline or template file? - - We can store our component's template in one of two places. - We can define it *inline* using the `template` property, as we do here. - Or we can define the template in a separate HTML file and link to it in - the component metadata using the `@Component` decorator's `templateUrl` property. - - The choice between inline and separate HTML is a matter of taste, - circumstances, and organization policy. - Here we're using inline HTML because the template is small, and the demo - is simpler without the additional HTML file. - - In either style, the template data bindings have the same access to the component's properties. - - - -.l-main-section -:marked - ## Showing a list property with ***ngFor** - - We want to display a list of heroes. We begin by adding a list of hero names to the component and redefine `myHero` to be the first name in the list. -+makeExample('displaying-data/dart/lib/app_component_2.dart', 'mock-heroes', 'lib/app_component.dart (excerpt)')(format=".") - -:marked - Now we use the Angular `ngFor` "repeater" directive in the template to display - each item in the `heroes` list. - -+makeExample('displaying-data/dart/lib/app_component_2.dart', 'template','lib/app_component.dart (excerpt)')(format=".") - - -:marked - Our presentation is the familiar HTML unordered list with `
    ` and `
  • ` tags. Let's focus on the `
  • ` tag. -+makeExample('displaying-data/dart/lib/app_component_2.dart', 'li-repeater')(format=".") - -:marked - We added a somewhat mysterious `*ngFor` to the `
  • ` element. - That's the Angular "repeater" directive. - Its presence on the `
  • ` tag marks that `
  • ` element (and its children) as the "repeater template". - -.alert.is-important +block hero-class :marked - Don't forget the leading asterisk (\*) in `*ngFor`. It is an essential part of the syntax. - Learn more about this and `ngFor` in the [Template Syntax](./template-syntax.html#ngFor) chapter. - -:marked - Notice the `hero` in the `ngFor` double-quoted instruction; - it is an example of a [template input variable](./template-syntax.html#ngForMicrosyntax). - - Angular duplicates the `
  • ` for each item in the list, setting the `hero` variable - to the item (the hero) in the current iteration. Angular uses that variable as the - context for the interpolation in the double curly braces. - -.l-sub-section - :marked - We happened to give `ngFor` a list to display. - In fact, `ngFor` can repeat items for any [Iterable](https://api.dartlang.org/stable/dart-core/Iterable-class.html) object. - -:marked - Now the heroes appear in an unordered list. - -figure.image-display - img(src="/resources/images/devguide/displaying-data/hero-names-list.png" alt="After ngfor") - -.callout.is-important - header Did the app break? - :marked - If the app stops working after adding `*ngFor`, - make sure `pubspec.yaml` has the [correct **platform_directives** entry](#platform_directives). - A missing or incorrect `platform_directives` entry results in template parse errors. - -.l-main-section -:marked - ## Creating a class for the data - - We are defining our data directly inside our component. - That's fine for a demo but certainly isn't a best practice. It's not even a good practice. - Although we won't do anything about that in this chapter, we'll make a mental note to fix this down the road. - - At the moment, we're binding to a list of strings. We do that occasionally in real applications, but - most of the time we're binding to more specialized objects. - - Let's turn our list of hero names into a list of `Hero` objects. For that we'll need a `Hero` class. - - Create a new file in the `lib/` folder called `hero.dart` with the following code. -+makeExample('displaying-data/dart/lib/hero.dart',null,'lib/hero.dart') - -:marked - We've defined a class with a constructor, a string description, and two properties: `id` and `name`. - -.l-main-section -:marked - ## Using the Hero class - Let's make the `heroes` property in our component return a list of these Hero objects. -- var stylePattern = { otl: /(import.*$)|(final)|(new Hero.*$)/gm }; -+makeExample('displaying-data/dart/lib/app_component_3.dart', 'heroes', 'app_component.dart (excerpt)', stylePattern)(format=".") - -:marked - We'll have to update the template. - At the moment it displays the string value of the `Hero` object. - Let's fix that so we display only the hero's `name` property. -- var stylePattern = { otl: /(myHero\.name)|(hero\.name)/gm }; -+makeExample('displaying-data/dart/lib/app_component_3.dart', 'template','app_component.dart (template)', stylePattern)(format=".") - - -:marked - Our display looks the same, but now we know much better what a hero really is. - - -.l-main-section -:marked - ## Conditional display with NgIf - - Sometimes the app should display a view or a portion of a view only under specific circumstances. - - In our example, we'd like to display a message if we have a large number of heroes — say, more than 3. - - The Angular `ngIf` directive inserts or removes an element based on a boolean condition. - We can see it in action by adding the following paragraph at the bottom of the template: -+makeExample('displaying-data/dart/lib/app_component.dart', 'message') -.alert.is-important - :marked - Don't forget the leading asterisk (\*) in `*ngIf`. It is an essential part of the syntax. - Learn more about this and `ngIf` in the [Template Syntax](./template-syntax.html#ngIf) chapter. - -:marked - The [template expression](./template-syntax.html#template-expressions) inside the double quotes - looks much like Dart, and it _is_ much like Dart. - When the component's list of heroes has more than 3 items, Angular adds the paragraph to the DOM and the message appears. - If there are 3 or fewer items, Angular omits the paragraph, so no message appears. - -.alert.is-helpful - :marked - Angular isn't showing and hiding the message. It is adding and removing the paragraph element from the DOM. - That hardly matters here. But it would matter a great deal, from a performance perspective, if - we were conditionally including or excluding a big chunk of HTML with many data bindings. - -:marked - Try it out. Because the list has four items, the message should appear. - Go back into `app_component.dart` and delete or comment out one of the elements from the hero list. - The browser should refresh automatically and the message should disappear. - -.l-main-section -:marked - ## Summary - Now we know how to use: - - **interpolation** with double curly braces to display a component property - - **`ngFor`** to display a list of items - - a Dart class to shape the **model data** for our component and display properties of that model - - **`ngIf`** to conditionally display a chunk of HTML based on a boolean expression - - Here's our final code: - -+makeTabs(`displaying-data/dart/lib/app_component.dart, - displaying-data/dart/lib/hero.dart, - displaying-data/dart/pubspec.yaml, - displaying-data/dart/web/index.html, - displaying-data/dart/web/main.dart`, - ',,,,final', - 'lib/app_component.dart, lib/hero.dart, pubspec.yaml, web/index.html, web/main.dart') + We've defined a class with a constructor, two properties (`id` and `name`), + and a `toString()` method. + +block final-code + +makeTabs(`displaying-data/dart/lib/app_component.dart, + displaying-data/dart/lib/hero.dart, + displaying-data/dart/pubspec.yaml, + displaying-data/dart/web/index.html, + displaying-data/dart/web/main.dart`, + ',,,,final', + 'lib/app_component.dart, lib/hero.dart, pubspec.yaml, web/index.html, web/main.dart') diff --git a/public/docs/ts/latest/guide/displaying-data.jade b/public/docs/ts/latest/guide/displaying-data.jade index dd46ce09a3..5fbf0e7ff7 100644 --- a/public/docs/ts/latest/guide/displaying-data.jade +++ b/public/docs/ts/latest/guide/displaying-data.jade @@ -1,34 +1,34 @@ -include ../_util-fns - - - +block includes + include ../_util-fns + - var _iterableUrl = 'https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols'; + - var _boolean = 'truthy/falsey'; + :marked We typically display data in Angular by binding controls in an HTML template to properties of an Angular component. In this chapter, we'll create a component with a list of heroes. Each hero has a name. We'll display the list of hero names and - conditionally show a selected hero in a detail area below the list. + conditionally show a message below the list. The final UI looks like this: figure.image-display img(src="/resources/images/devguide/displaying-data/final.png" alt="Final UI") - + :marked # Table Of Contents - + * [Showing component properties with interpolation](#interpolation) - * [Showing an array property with NgFor](#ngFor) + * [Showing !{_an} !{_array} property with NgFor](#ngFor) * [Conditional display with NgIf](#ngIf) - + .l-sub-section :marked - The [live example](/resources/live-examples/displaying-data/ts/plnkr.html) - demonstrates all of the syntax and code snippets described in this chapter. + The demonstrates all of the syntax and code + snippets described in this chapter. - -.l-main-section +.l-main-section#interpolation :marked ## Showing component properties with interpolation The easiest way to display a component property @@ -37,14 +37,17 @@ figure.image-display Let's build a small illustrative example together. - Create a new project folder (`displaying-data`) and follow the steps in the [QuickStart](../quickstart.html). + Create a new project folder () and follow the steps in the [QuickStart](../quickstart.html). + +block quickstart-repo + include ../_quickstart_repo -include ../_quickstart_repo :marked - Then modify the `app.component.ts` file by changing the template and the body of the component. + Then modify the file by + changing the template and the body of the component. When we're done, it should look like this: -+makeExample('displaying-data/ts/app/app.component.1.ts', null, 'app/app.component.ts') ++makeExample('app/app.component.1.ts') :marked We added two properties to the formerly empty component: `title` and `myHero`. @@ -52,94 +55,99 @@ include ../_quickstart_repo Our revised template displays the two component properties using double curly brace interpolation: -+makeExample('displaying-data/ts/app/app.component.1.ts', 'template')(format=".") -.l-sub-section - :marked - The template is a multi-line string within ECMAScript 2015 backticks (\`). - The backtick (\`) — which is *not* the same character as a single - quote (') — has many nice features. The feature we're exploiting here - is the ability to compose the string over several lines, which makes for - much more readable HTML. ++makeExcerpt('app/app.component.1.ts', 'template', '') + ++ifDocsFor('ts') + .l-sub-section + :marked + The template is a multi-line string within ECMAScript 2015 backticks (\`). + The backtick (\`) — which is *not* the same character as a single + quote (`'`) — has many nice features. The feature we're exploiting here + is the ability to compose the string over several lines, which makes for + much more readable HTML. :marked Angular automatically pulls the value of the `title` and `myHero` properties from the component and inserts those values into the browser. Angular updates the display when these properties change. + .l-sub-section :marked More precisely, the redisplay occurs after some kind of asynchronous event related to the view such as a keystroke, a timer completion, or an async `XHR` response. We don't have those in this sample. But then the properties aren't changing on their own either. For the moment we must operate on faith. + :marked Notice that we haven't called **new** to create an instance of the `AppComponent` class. Angular is creating an instance for us. How? - Notice the CSS `selector` in the `@Component` decorator that specifies an element named "my-app". - Remember back in QuickStart that we added the `` element to the body of our `index.html` -+makeExample('displaying-data/ts/index.html', 'my-app')(format=".") + Notice the CSS `selector` in the `@Component` !{_decorator} that specifies an element named `my-app`. + Remember back in [QuickStart](../quickstart.html) that we added the `` element to the body of our `index.html` file: + ++makeExcerpt('index.html', 'body') :marked - When we bootstrap with the `AppComponent` class (see `main.ts`), Angular looks for a `` + When we bootstrap with the `AppComponent` class (in ), Angular looks for a `` in the `index.html`, finds it, instantiates an instance of `AppComponent`, and renders it inside the `` tag. - We're ready to see changes in a running app by firing up the npm script that both compiles and serves our applications - while watching for changes. -code-example(format=""). - npm start -:marked - We should see the title and hero name: + Try running the app. It should display the title and hero name: figure.image-display img(src="/resources/images/devguide/displaying-data/title-and-hero.png" alt="Title and Hero") -:marked - Let's review some of the choices we made and consider alternatives. ++ifDocsFor('ts') + :marked + Let's review some of the choices we made and consider alternatives. + +:marked ## Template inline or template file? We can store our component's template in one of two places. We can define it *inline* using the `template` property, as we do here. Or we can define the template in a separate HTML file and link to it in - the component metadata using the `@Component` decorator's `templateUrl` property. + the component metadata using the `@Component` !{_decorator}'s `templateUrl` property. The choice between inline and separate HTML is a matter of taste, circumstances, and organization policy. Here we're using inline HTML because the template is small, and the demo - is simpler without the HTML file. + is simpler without the additional HTML file. In either style, the template data bindings have the same access to the component's properties. - ## Constructor or variable initialization? ++ifDocsFor('ts') + :marked + ## Constructor or variable initialization? - We initialized our component properties using variable assignment. - This is a wonderfully concise and compact technique. + We initialized our component properties using variable assignment. + This is a wonderfully concise and compact technique. - Some folks prefer to declare the properties and initialize them within a constructor like this: -+makeExample('displaying-data/ts/app/app-ctor.component.ts', 'app-ctor')(format=".") + Some folks prefer to declare the properties and initialize them within a constructor like this: + +makeExcerpt('app/app-ctor.component.ts', 'class') -:marked - That's fine too. The choice is a matter of taste and organization policy. - We'll adopt the more terse "variable assignment" style in this chapter simply because - there will be less code to read. + :marked + That's fine too. The choice is a matter of taste and organization policy. + We'll adopt the more terse "variable assignment" style in this chapter simply because + there will be less code to read. - -.l-main-section +.l-main-section#ngFor :marked - ## Showing an array property with ***ngFor** + ## Showing !{_an} !{_array} property with ***ngFor** + + We want to display a list of heroes. We begin by adding !{_an} !{_array} of hero names to the component and redefine `myHero` to be the first name in the !{_array}. - We want to display a list of heroes. We begin by adding a mock heroes name array to the component, - just above `myHero`, and redefine `myHero` to be the first name in the array. -+makeExample('displaying-data/ts/app/app.component.2.ts', 'mock-heroes', 'app/app.component.ts (class)')(format=".") ++makeExcerpt('app/app.component.2.ts', 'class') :marked - Now we use the Angular `ngFor` "repeater" directive in the template to display + Now we use the Angular `ngFor` directive in the template to display each item in the `heroes` list. -+makeExample('displaying-data/ts/app/app.component.2.ts', 'template','app/app.component.ts (template)')(format=".") ++makeExcerpt('app/app.component.2.ts', 'template') :marked Our presentation is the familiar HTML unordered list with `
      ` and `
    • ` tags. Let's focus on the `
    • ` tag. -+makeExample('displaying-data/ts/app/app.component.2.ts', 'li-repeater')(format=".") + ++makeExcerpt('app/app.component.2.ts ()', 'li', '') :marked We added a somewhat mysterious `*ngFor` to the `
    • ` element. @@ -152,7 +160,7 @@ figure.image-display Learn more about this and `ngFor` in the [Template Syntax](./template-syntax.html#ngFor) chapter. :marked - Notice the `hero` in the `ngFor` double-quoted instruction; + Notice the `hero` in the `ngFor` double-quoted instruction; it is an example of a [template input variable](./template-syntax.html#ngForMicrosyntax). Angular duplicates the `
    • ` for each item in the list, setting the `hero` variable @@ -161,12 +169,11 @@ figure.image-display .l-sub-section :marked - We happened to give `ngFor` an array to display. - In fact, `ngFor` can repeat items for any [iterable](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) + We happened to give `ngFor` !{_an} !{_array} to display. + In fact, `ngFor` can repeat items for any [iterable](!{_iterableUrl}) object. :marked - Assuming we're still running under the `npm start` command, - we should see heroes appearing in an unordered list. + Now the heroes appear in an unordered list. figure.image-display img(src="/resources/images/devguide/displaying-data/hero-names-list.png" alt="After ngfor") @@ -179,57 +186,62 @@ figure.image-display That's fine for a demo but certainly isn't a best practice. It's not even a good practice. Although we won't do anything about that in this chapter, we'll make a mental note to fix this down the road. - At the moment, we're binding to an array of strings. We do that occasionally in real applications, but - most of the time we're displaying objects — potentially instances of classes. + At the moment, we're binding to !{_an} !{_array} of strings. We do that occasionally in real applications, but + most of the time we're binding to more specialized objects. - Let's turn our array of hero names into an array of `Hero` objects. For that we'll need a `Hero` class. + Let's turn our !{_array} of hero names into !{_an} !{_array} of `Hero` objects. For that we'll need a `Hero` class. - Create a new file in the `app/` folder called `hero.ts` with the following short bit of code. -+makeExample('displaying-data/ts/app/hero.ts', null, 'app/hero.ts')(format = ".") + Create a new file in the `!{_appDir}` folder called with the following code: + ++makeExcerpt('app/hero.ts') -:marked - We've defined a class with a constructor and two properties: `id` and `name`. +block hero-class + :marked + We've defined a class with a constructor and two properties: `id` and `name`. - It might not look like we have properties, but we do. We're taking - advantage of a TypeScript shortcut in our declaration of the constructor parameters. + It might not look like we have properties, but we do. We're taking + advantage of a TypeScript shortcut in our declaration of the constructor parameters. - Consider the first parameter: -+makeExample('displaying-data/ts/app/hero.ts', 'id-parameter') + Consider the first parameter: -:marked - That brief syntax does a lot: - * declares a constructor parameter and its type - * declares a public property of the same name - * initializes that property with the corresponding argument when we "new" an instance of the class + +makeExcerpt('app/hero.ts ()', 'id') + + :marked + That brief syntax does a lot: + * Declares a constructor parameter and its type + * Declares a public property of the same name + * Initializes that property with the corresponding argument when we "new" an instance of the class .l-main-section :marked ## Using the Hero class - Let's redefine the `heroes` property in our component to return an array of these Hero objects - and also set the `myHero` property with the first of these mock heroes. -+makeExample('displaying-data/ts/app/app.component.3.ts', 'heroes', 'app.component.ts (excerpt)')(format=".") + Let's make the `heroes` property in our component return !{_an} !{_array} of these `Hero` objects. + ++makeExcerpt('app/app.component.3.ts', 'heroes') :marked We'll have to update the template. - At the moment it displays the entire `hero` object, which used to be a string value. - Let's fix that so we interpolate the `hero.name` property. -+makeExample('displaying-data/ts/app/app.component.3.ts', 'template','app.component.ts (template)')(format=".") + At the moment it displays the hero's `id` and `name`. + Let's fix that so we display only the hero's `name` property. + ++makeExcerpt('app/app.component.3.ts', 'template') :marked Our display looks the same, but now we know much better what a hero really is. - -.l-main-section +.l-main-section#ngIf :marked ## Conditional display with NgIf - Sometimes the app should display a view or a portion of a view only under specific circumstances. + Sometimes an app needs to display a view or a portion of a view only under specific circumstances. - In our example, we'd like to display a message if we have a large number of heroes — say, more than 3. + In our example, we'd like to display a message if we have a large number of heroes, say, more than 3. - The Angular `ngIf` directive inserts or removes an element based on a truthy/falsey condition. + The Angular `ngIf` directive inserts or removes an element based on a !{_boolean} condition. We can see it in action by adding the following paragraph at the bottom of the template: -+makeExample('displaying-data/ts/app/app.component.ts', 'message') + ++makeExcerpt('app/app.component.ts', 'message') + .alert.is-important :marked Don't forget the leading asterisk (\*) in `*ngIf`. It is an essential part of the syntax. @@ -237,7 +249,7 @@ figure.image-display :marked The [template expression](./template-syntax.html#template-expressions) inside the double quotes - looks much like JavaScript and it _is_ much like JavaScript. + looks much like !{_Lang}, and it _is_ much like !{_Lang}. When the component's list of heroes has more than 3 items, Angular adds the paragraph to the DOM and the message appears. If there are 3 or fewer items, Angular omits the paragraph, so no message appears. @@ -248,23 +260,24 @@ figure.image-display we were conditionally including or excluding a big chunk of HTML with many data bindings. :marked - Try it out. Because the array has four items, the message should appear. - Go back into `app.component.ts` and delete or comment out one of the elements from the hero array. + Try it out. Because the !{_array} has four items, the message should appear. + Go back into and delete or comment out one of the elements from the hero !{_array}. The browser should refresh automatically and the message should disappear. .l-main-section :marked ## Summary Now we know how to use: - - **interpolation** with double curly braces to display a component property - - **`ngFor`** to display a list of items - - a TypeScript class to shape the **model data** for our component and display properties of that model - - **`ngIf`** to conditionally display a chunk of HTML based on a boolean expression + - **Interpolation** with double curly braces to display a component property + - **ngFor** to display !{_an} !{_array} of items + - A !{_Lang} class to shape the **model data** for our component and display properties of that model + - **ngIf** to conditionally display a chunk of HTML based on a boolean expression Here's our final code: -+makeTabs(`displaying-data/ts/app/app.component.ts, - displaying-data/ts/app/hero.ts, - displaying-data/ts/app/main.ts`, - 'final,,', - 'app/app.component.ts, app/hero.ts, main.ts') +block final-code + +makeTabs(`displaying-data/ts/app/app.component.ts, + displaying-data/ts/app/hero.ts, + displaying-data/ts/app/main.ts`, + 'final,,', + 'app/app.component.ts, app/hero.ts, main.ts')