include _util-fns

// #docregion intro
:marked
  # Angular 2词汇表

  Angular 2 has a vocabulary of its own.
  Most Angular 2 terms are everyday English words
  with a specific meaning within the Angular system.

  Angular 2有自己的词汇表。
  虽然大多数的Angular 2短语都是日常用语，但是在Angular体系中，它们有特别的含义。

  We have gathered here the most prominent terms
  and a few less familiar ones that have unusual or
  unexpected definitions.

  我们搜集了常用词和少量具有独特或反直觉含义的罕用词。

  [A](#A) [B](#B) [C](#C) [D](#D) [E](#E) [F](#F) [G](#G) [H](#H) [I](#I)
  [J](#J) [K](#K) [L](#L) [M](#M) [N](#N) [O](#O) [P](#P) [Q](#Q) [R](#R)
  [S](#S) [T](#T) [U](#U) [V](#V) [W](#W) [X](#X) [Y](#Y) [Z](#Z)
// #enddocregion intro

// #docregion a1
<a id="A"></a>
// #enddocregion a1
.l-main-section
:marked
  ## Annotation
  ## 注解（Annotation）
.l-sub-section
  :marked
    In practice a synonym for [Decoration](#decorator).
    
    [装饰器（Decoration）](#decorator)在实践中的同义词。
// #enddocregion a-1
// #docregion a-2
:marked
  ## Attribute Directive
  ## 属性型指令（Attribute Directive）
.l-sub-section
  :marked
    A category of [Directive](#directive) that can listen to and modify the behavior of
    other HTML elements, attributes, properties, and components. They are usually represented
    as HTML attributes, hence the name.

    [指令](#directive)分类中的一种。它允许监听或修改其它HTML元素、属性、组件的行为。它们通常用作HTML属性，就像它的名字所暗示的那样。
    
    The `ngClass` directive for adding and removing CSS class names is a good example of
    an Attribute Directive.
    
    `ngClass`指令就是典型的属性型指令。它可以添加或移除CSS类名。
// #enddocregion a-2

// #docregion b-c
- var lang = current.path[1]
- var decorator = lang === 'dart' ? 'annotation' : '<a href="#decorator">decorator</a>'
- var atSym = lang === 'js' ? '' : '@'
<a id="B"></a>
.l-main-section
:marked
  ## Barrel
  ## 封装桶（Barrel）
.l-sub-section
  :marked
    A barrel is a way to *rollup exports* from several modules into a single convenience module.
    The barrel itself is a module file that re-exports *selected* exports of other modules.
    
    封装桶是把一系列模块中的 *导出结果* 归纳进一个单一的快捷模块的一种方式。
    封装桶本身是一个模块文件，它重新导出来自其它模块的 *选中的* 导出
    
    Imagine three modules in a `heroes` folder:
    
    假设在`heroes`目录下有三个模块：
  code-example(format='').
    // heroes/hero.component.ts
    export class HeroComponent {}
    
    // heroes/hero.model.ts
    export class Hero {}
    
    // heroes/hero.service.ts
    export class HeroService {}
  :marked
    Without a barrel, a consumer would need three import statements:
    
    假如没有封装桶，消费者就需要三条import语句：
  code-example(format='').
    import { HeroComponent } from '../heroes/hero.component.ts';
    import { Hero }          from '../heroes/hero.model.ts';
    import { HeroService }   from '../heroes/hero.service.ts';
  :marked
    We can add a barrel to the `heroes` folder (called `index` by convention) that exports all of these items:
    
    我们可以在`heroes`目录下添加一个封装桶（按规约叫做`index`），它导出所有这三条：
  code-example(format='').
    import * from './hero.model.ts';   // re-export all of its exports
    import * from './hero.service.ts'; // re-export all of its exports
    export { HeroComponent } from './hero.component.ts'; // re-export the named thing
  :marked
    Now a consumer can import what it needs from the barrel.
    
    现在，消费者就可以从这个封装桶中导入它需要的东西了。
  code-example(format='').
    import { Hero, HeroService } from '../heroes'; // index is implied
  :marked
    The Angular [scoped packages](#scoped-package) each have a barrel named `index`.
    
    Angular的每个[范围化包](#scoped-package)都有一个叫做`index`的封装桶。
// #enddocregion b-c
:marked
  That's why we can write this:
  
  这就是为什么我们可以这样写的原因：
+makeExample('../docs/_fragments/quickstart/ts/app/app.component.ts', 'import')(format=".")
// #docregion b-c

:marked
  ## Binding
  ## 绑定
.l-sub-section
  :marked
    Almost always refers to [Data Binding](#data-binding) and the act of
    binding an HTML object property to a data object property.

    几乎都是指的[数据绑定](#data-binding)和将一个HTML对象属性绑定到一个数据对象属性的行为。

    May refer to a [Dependency Injection](#dependency-injection) binding
    between a "token" or "key" and a dependency [provider](#provider).
    This more rare usage should be clear in context.

    有可能指的是[依赖注入](#dependency-injection)在一个Token或Key和一个依赖的[Provider](#provider)之间的绑定。
    这种用法很少，而且一般都会在上下文中写清楚。

:marked
  ## Bootstrap
  ## 启动/引导
.l-sub-section
  :marked
    We launch an Angular application by "bootstrapping" it with the `bootstrap` method.
    The `bootstrap` method identifies an application's top level "root" [Component](#component)
    and optionally registers service [providers](#provider) with the
    [dependency injection system](#dependency-injection).

    我们通过一个名叫`bootstrap`的类方法来引导Angular应用程序。这个`bootstrap`类方法会识别应用程序的顶级“根”[组件](#component)，
    并可能通过[依赖注入体系](#dependency-injection)注册服务的[Provider](#provider)。

    One can bootstrap multiple apps in the same `index.html`, each with its own top level root.
    
    你可以在同一个`index.html`中引导多个应用，每个应用都有自己的顶级根组件。

<a id="C"></a>
.l-main-section
:marked
  ## camelCase
  ## 驼峰式命名法
.l-sub-section
  :marked
    The practice of writing compound words or phrases such that each word or abbreviation begins with a capital letter 
    _except the first letter which is a lowercase letter_. 

    驼峰式命名法是指除了首字母要小写外，每个单词或缩写都以大写字母开头儿的形式来书写复合词或短语的一种实践。

    Function, property, and method names are typically spelled in camelCase. Examples include: `square`, `firstName` and `getHeroes`.

    函数、属性和方法命名一般都使用驼峰式拼写法。比如`square`, `firstName` 和 `getHeroes`等。

    This form is also known as **lower camel case**, to distinguish it from **upper camel case** which we call [PascalCase](#pascalcase).
    When we write "camelCase" in this documentation we always mean *lower camel case*.

    这种形式也被叫做**小驼峰式命名法（lower camel case）**，以区分于**大驼峰式命名法**（我们也叫Pascal命名法）。
    当我们在文档中提到“驼峰式命名法（camelCase）”的时候，所指的都是小驼峰命名法。

:marked
  ## Component
  ## 组件
.l-sub-section
  :marked
    An Angular class responsible for exposing data
    to a [View](#view) and handling most of the view’s display
    and user-interaction logic.

    组件是一个用来把数据展示到[视图](#view)，并处理几乎所有视图显示以及用户交互逻辑的Angular类。

    The Component is one of the most important building blocks in the Angular system.
    It is, in fact, an Angular [Directive](#directive) with a companion [Template](#template).

    组件是Angular系统的最重要的基本构造块儿之一。
    它其实是一个拥有[模板](#template)的[指令](#directive)。

    The  developer applies the `#{atSym}Component` !{decorator} to
    the component class, thereby attaching to the class the essential component metadata
    that Angular needs to create a component instance and render it with its template
    as a view.

    开发人员使用`#{atSym}Component`!{decoratorCn}来装饰一个组件类，也就是把这个核心组件的元数据附加到类上。
    Angular利用这个元数据信息，来创建一个组件实例，并把组件的模板作为视图渲染出来。

    Those familiar with "MVC" and "MVVM" patterns will recognize
    the Component in the role of "Controller" or "View Model".

    如果你熟悉 "MVC" 和 "MVVM" 架构模式，就会意识到“组件”充当了“控制器”和“视图模型”的角色。
// #enddocregion b-c

// #docregion d1
<a id="D"></a>
.l-main-section
:marked
  ## dash-case
  ## 中线命名法
.l-sub-section
  :marked
    The practice of writing compound words or phrases such that each word is separated by a dash or hyphen (-). 

    使用中线来分隔每个单词来编写词汇或短语的方法叫做中线命名法（dash-case）。

    Directive selectors and the root of filenames are often spelled in dash-case. Examples include: `my-app` and the `hero-list.component.ts`.

    指令的选择器和文件名通常都是通过中线命名法来命名的。比如`my-app` 和 `hero-list.component.ts`。

    This form is also known as [kebab-case](#kebab-case).

    这种命名法也被称为烤串命名法[kebab-case](#kebab-case)。

:marked
  ## Data Binding
  ## 数据绑定
.l-sub-section
  :marked
    Applications display data values to a user and respond to user
    actions (clicks, touches, keystrokes).

    应用程序会将数据展示给用户，并对用户的操作（点击、触屏、按键）做出回应。
    
    We could push application data values into HTML, attach
    event listeners, pull changed values from the screen, and
    update application data values ... all by hand.
    
    我们当然可以自己处理这些操作：将数据显示到HTML网页，添加事件监听器，从屏幕获取数据变化，然后更新数据等等……

    Or we could declare the relationship between an HTML widget
    and an application data source ... and let a data binding
    framework handle the details.
    
    或者，我们也可以声明HTML小部件和数据源的关系……，让一个数据绑定框架来处理所有细节。

    Data Binding is that second approach. Angular has a rich
    data binding framework with a variety of data binding
    operations and supporting declaration syntax.
    
    这第二种方法就是数据绑定。Angular有一个非常强大的数据绑定框架，具有多种用来数据绑定的操作，并支持声明语法规则。

     The many forms of binding include:
     绑定形式包括：
     * [Interpolation](guide/template-syntax.html#interpolation)
     * [插值表达式（Interpolation）](guide/template-syntax.html#interpolation)
     * [Property Binding](guide/template-syntax.html#property-binding)
     * [属性绑定（Property Binding）](guide/template-syntax.html#property-binding)
     * [Event Binding](guide/template-syntax.html#event-binding)
     * [事件绑定（Event Binding）](guide/template-syntax.html#event-binding)
     * [Attribute Binding](guide/template-syntax.html#attribute-binding)
     * [Attribute绑定（Attribute Binding）](guide/template-syntax.html#attribute-binding)
     * [Class Binding](guide/template-syntax.html#class-binding)
     * [类绑定（Class Binding）](guide/template-syntax.html#class-binding)
     * [Style Binding](guide/template-syntax.html#style-binding)
     * [样式绑定（Style Binding）](guide/template-syntax.html#style-binding)
     * [Two-way data binding with ngModel](guide/template-syntax.html#ng-model)
     * [基于ngModel的双向数据绑定（Two-way data binding with ngModel）](guide/template-syntax.html#ng-model)
     
    Learn more about data binding in the
    [Template Syntax](guide/template-syntax.html#data-binding) chapter.
    
    要了解关于数据绑定的更多知识，请参见[模板语法](guide/template-syntax.html#data-binding)一章。

// #enddocregion d1
<a id="decorator"></a> <a id="decoration"></a>
:marked
  ## Decorator | Decoration
  ## 装饰器
.l-sub-section
  :marked
    A Decorator is a **function** that adds metadata to a class, its members (properties, methods) and function arguments.
    
    装饰器是一个**函数**，这个函数将元数据添加到类、类成员（属性、方法）和函数上。
    
    Decorators are a JavaScript language [feature](https://github.com/wycats/javascript-decorators), implemented in TypeScript and proposed for ES2016 (AKA ES7).
    
    装饰器是一个JavaScript的语言[特征](https://github.com/wycats/javascript-decorators)，装饰器在TypeScript里面已经采纳并实现了，并被推荐到了ES2016（也就是ES7）。

    We apply a decorator by positioning it
    immediately above or to the left of the thing it decorates.
    
    我们应用装饰器的方法是把装饰器放到被装饰对象的上面或左边。

    Angular has its own set of decorators to help it interoperate with our application parts.
    Here is an example of a `@Component` decorator that identifies a
    class as an Angular [Component](#component) and an `@Input` decorator applied to a property
    of that component.
    
    Angular使用自己的一套装饰器来实现应用程序各部分之间的相互操作。
    下面的例子中使用了`@Component`装饰器来将一个类标记为一个Angular[组件](#component)，并用`@Input`装饰器来装饰该组件的一个属性。
    
    The elided object argument to the `@Component` decorator would contain the pertinent component metadata.
    
    `@Component`装饰器中被省略的参数对象还可以包含和组件有关的元数据。
    
    ```
    @Component({...})
    export class AppComponent {
      constructor(@Inject('SpecialFoo') public foo:Foo) {}
      @Input()
      name:string;
    }
    ```
    
    The scope of a decorator is limited to the language feature
    that it decorates. None of the decorations shown here will "leak" to other
    classes appearing below it in the file.
    
    一个装饰器的作用范围会被限制在它所装饰的东西上，这是一个语言级特性。在上面这个例子中，就算其它类在同一个文件中紧跟着上面的类也不会有任何装饰器“泄露”到其它类。

  .alert.is-important
    :marked
      Always include the parentheses `()` when applying a decorator.
      A decorator is a **function** that must be called when applied.
      
      永远别忘了在装饰器后面加括号`()`。因为装饰器是 **函数** ，在应用它的时候一定要被调用。

// #docregion d2
:marked
  ## Dependency Injection
  ## 依赖注入
.l-sub-section
  :marked
    Dependency Injection is both a design pattern and a mechanism
    for creating and delivering parts of an application to other
    parts of an application that request them.
    
    依赖注入既是设计模式，同时也是一种机制：当应用程序的一些部件需要另一些部件的时候，使用依赖注入机制来创建被请求的部件并将其注入到发出请求的部件。

    Angular developers prefer to build applications by defining many simple parts
    that each do one thing well and then wire them together at runtime.
    
    Angular开发者喜欢的构建应用程序的方法是：定义许多精简小部件，每个小部件只做一件事并做好它，然后在运行期把这些精简小部件装配在一起组成应用程序。

    These parts often rely on other parts. An Angular [Component](#component)
    part might rely on a service part to get data or perform a calculation. When a
    part "A" relies on another part "B", we say that "A" depends on "B" and
    that "B" is a dependency of "A".
    
    这些小部件通常会依赖其它小部件。一个Angular[组件](#component)可能依赖一个“服务”部件来获取数据或者处理运算。当部件A要靠另一个部件B才能工作，我们就说A依赖B，B是A的“依赖”。

    We can ask a "Dependency Injection System" to create "A"
    for us and handle all the dependencies.
    If "A" needs "B" and "B" needs "C", the system resolves that chain of dependencies
    and returns a fully prepared instance of "A".
    
    我们可以让“依赖注入系统”为我们创建一个部件A并处理所有A的“依赖”。如果A需要B，B需要C，这个系统便解析这个依赖链，给我们返回一个完全准备好的A实例。

    Angular provides and relies upon its own sophisticated
    [Dependency Injection](dependency-injection.html) system
    to assemble and run applications by "injecting" application parts
    into other application parts where and when needed.
    
    Angular提供并使用自己设计精密的[依赖注入](dependency-injection.html)系统来组装和运行应用程序：在要用时，将一些部件“注入”到另一些部件里面。

    At the core is an [`Injector`](#injector) that returns dependency values on request.
    The expression `injector.get(token)` returns the value associated with the given token.
    
    依赖注入的核心是一个[`Injector`](#injector)，这个注入器按需返回依赖部件。`injector.get(token)`方法返回和提供的Token参数相关的依赖部件。

    A token is an Angular type (`OpaqueToken`). We rarely deal with tokens directly; most
    methods accept a class name (`Foo`) or a string ("foo") and Angular converts it
    to a token. When we write `injector.get(Foo)`, the injector returns
    the value associated with the token for the `Foo` class, typically an instance of `Foo` itself.
    
    Token是一个Angular中的类型(`OpaqueToken`)。我们很少需要直接接触Token。绝大多数类方法都接受类名称 (`Foo`)或者字符串("foo")，Angular把这些类名称和字符串转换为Token。
    当我们调用`injector.get(Foo)`时，注入器返回用`Foo`类生成的的Token对应的依赖值，这个依赖值通常是`Foo`类的实例。

    Angular makes similar requests internally during many of its operations
    as when it creates a [`Component`](#AppComponent) for display.
    
    Angular在创建[组件](#AppComponent)以供显示的过程中，会在内部执行很多类似的依赖注入请求。

    The `Injector` maintains an internal map of tokens to dependency values.
    If the `Injector` can't find a value for a given token, it creates
    a new value using a `Provider` for that token.
    
    `注入器`维护一个Token与其对应的依赖值对照图。如果`Injector`不能找到一个Token对应的依赖值，它就会使用`Provider`来创建一个依赖值。

    A [Provider](#provider) is a recipe for
    creating new instances of a dependency value associated with a particular token.
    
    `Provider`(#provider)是使用指定Token来创建相应依赖实例的“菜谱”之一。

    An injector can only create a value for a given token if it has
    a `Provider` for that token in its internal provider registry.
    Registering providers is a critical preparatory step.
    
    如果在注入器的内部注册表中，一个Token对应的依赖值是一个`Provider`，那么注入器就得为这个Token创建一个依赖值。所以注册Provider是一个非常关键的准备步骤。

    Angular registers some of its own providers with every injector.
    We can register our own providers. Quite often the best time to register a `Provider`
    is when we [bootstrap](#bootstrap) the application.
    There are other opportunities to register as well.
    
    Angular会为每个注册器注册很多自己的内置Provider。我们也可以注册自己的Provider。通常注册Provider的最佳时间是在应用程序开始[引导](#bootstrap)的时候。
    当然，我们也有其它很多机会注册Provider。

    Learn more in the [Dependency Injection](guide/dependency-injection.html) chapter.
    
    要了解关于依赖注入的更多知识，请参见[依赖注入](guide/dependency-injection.html)一章。
    
:marked
  ## Directive
  ## 指令
.l-sub-section
  :marked
    An Angular class responsible for creating, re-shaping, and interacting with HTML elements
    in the browser DOM. Directives are Angular's most fundamental feature.

    指令是一个Angular类，这个类负责创建和重塑浏览器DOM中的HTML元素，同时负责与HTML元素的互动。指令是Angular中最基本的特性。

    A Directive is almost always associated with an HTML element or attribute.
    We often refer to such an element or attribute as the directive itself.
    When Angular finds a directive in an HTML template,
    it creates the matching directive class instance
    and gives that instance control over that portion of the browser DOM.
    
    指令几乎都是关联到HTML元素或Attribute的。我们通常把这些关联的HTML元素或者Attribute当做指令本身。
    当Angular在HTML模板中遇到一个指令的时候，它就找出一个与该指令匹配的类，创建此类的实例，然后把浏览器中这部分DOM的控制权交给该实例。

    Developers can invent custom HTML markup (e.g., `<my-directive>`) to
    associate with their custom directives. They add this custom markup to HTML templates
    as if they were writing native HTML. In this way, directives become extensions of
    HTML itself.
    
    开发人员可以为自定义指令指定自定义的HTML标签（比如`<my-directive>`），然后，他们就可以像写原生HTML一样把这些自定义标签放到HTML模板里了。
    这样，指令就变成了HTML本身的拓展。

    Directives fall into one of three categories:
    
    指令包括了一下三个类别：
    
    1. [Components](#component) that combine application logic with an HTML template to
    render application [views]. Components are usually represented as HTML elements.
    They are the building blocks of an Angular application and the
    developer can expect to write a lot of them.    
    1. [组件](#component): 用来程序逻辑和一个用来渲染视图的HTML模板[views]。组件一般表示成HTML元素的形式。它们是用来构建Angular应用程序的基本单元。可以预料，开发人员将会写很多很多组件。

    1. [Attribute Directives](#attribute-directive) that can listen to and modify the behavior of
    other HTML elements, attributes, properties, and components. They are usually represented
    as HTML attributes, hence the name.
    1. [Attribute指令](#attribute-directive)：可以监控和修改其它HTML元素、Attribute、属性和组件之类的行为。它们一般表示为HTML元素Attibute，故名。

    1. [Structural Directives](#structural-directive), a directive responsible for
    shaping or re-shaping HTML layout, typically by adding, removing, or manipulating
    elements and their children.
    1. [结构型指令](#structural-directive)：负责塑造或重塑HTML布局。这一般是通过添加、删除或者操作HTML元素及其子元素来实现的。
// #enddocregion d2

// #docregion e1
<a id="E"></a>
// #enddocregion e1
// #docregion e2
.l-main-section
:marked
  ## ECMAScript  
.l-sub-section
  :marked
    The [official JavaScript language specification](https://en.wikipedia.org/wiki/ECMAScript).
    
    [官方JavaScript语言规范](https://en.wikipedia.org/wiki/ECMAScript)
    
    The latest approved version of JavaScript is
    [ECMAScript 2015](http://www.ecma-international.org/ecma-262/6.0/)
    (AKA "ES2015" or "ES6") and many Angular 2 developers will write their applications
    either in this version of the language or a dialect that strives to be
    compatible with it such as [TypeScript](#typesScript).
    
    最新的被认可的JavaScript版本是[ECMAScript 2015](http://www.ecma-international.org/ecma-262/6.0/)，（也叫“ES2015”或“ES6”）。Angular 2的开发者要么使用这个版本的JavaScript，要么使用与这个版本兼容的语言，比如[TypeScript](#typesScript)。
   
    Most modern browsers today only support the prior "ECMAScript 5" (AKA ES5) standard.
    Applications written in ES2015 or one of its dialects must be "[transpiled](#transpile)"
    to ES5 JavaScript.
    
    目前，几乎所有现代游览器都只支持上一个版本的“ECMAScript 5” （也就是ES5）标准。使用ES2015或者其它兼容语言开发的应用程序，都必须被“[转译](#transpile)”成ES5 JavaScript。

    Angular 2 developers may choose to write in ES5 directly.
    
    Angular 2的开发者也可以选择直接使用ES5编程。
    
:marked
  ## ECMAScript 2015  
.l-sub-section
  :marked
    The lastest released version of JavaScript,
    [ECMAScript 2015](http://www.ecma-international.org/ecma-262/6.0/)
    (AKA "ES2015" or "ES6")
    
    最新发布的JavaScript版本，[ECMAScript 2015](http://www.ecma-international.org/ecma-262/6.0/)
    (即 "ES2015" 或 "ES6")
:marked
  ## ES2015
.l-sub-section
  :marked
    Short hand for "[ECMAScript 2015](#ecmascript=2015)".
    
    “[ECMAScript 2015](#ecmascript=2015)”的简写。
:marked
  ## ES6
.l-sub-section
  :marked
    Short hand for "[ECMAScript 2015](#ecmascript=2015)".
    
    [ECMAScript 2015](#ecmascript=2015)的简写。
:marked
  ## ES5
.l-sub-section
  :marked
    Short hand for "ECMAScript 5", the version of JavaScript run by most modern browsers.
    See [ECMAScript](#ecmascript).
    
    “ECMAScript 5”的简写，大部分现代浏览器使用的JavaScript版本。参见[ECMAScript](#ecmascript)。
// #enddocregion e2

// #docregion f-l
<a id="F"></a>
<a id="G"></a>
<a id="H"></a>
<a id="I"></a>
.l-main-section
:marked
  ## Injector
  ## 注入器
.l-sub-section
  :marked
    An object in the Angular [dependency injection system](#dependency-injection)
    that can find a named "dependency" in its cache or create such a thing
    with a registered [provider](#provider).

    Angular[依赖注入系统](#dependency-injection)中的一个对象，它可以在自己的缓存中找到一个“有名字的依赖”或者利用一个已注册的[provider](#provider)创建这样的依赖。
:marked
  ## Input
.l-sub-section
  :marked
    A directive property that can be the ***target*** of a
    [Property Binding](guide/template-syntax.html#property-binding).
    Data values flow *into* this property from the data source identified
    in the template expression to the right of the equal sign.
    
    指令属性可以作为[属性绑定](guide/template-syntax.html#property-binding)的目标。数据值会从模板表达式等号右侧的数据源中，流入这个属性。

    See the [Template Syntax](guide/template-syntax.html#inputs-outputs) chapter.
    
    参见[模板语法Template Syntax](guide/template-syntax.html#inputs-outputs)一章。

:marked
  ## Interpolation
  ## 插值表达式
.l-sub-section
  :marked
    A form of [Property Data Binding](#data-binding) in which a
    [template expression](#template-expression) between double-curly braces
    renders as text.  That text may be concatenated with neighboring text
    before it is assigned to an element property
    or displayed between element tags as in this example.
    
    [属性数据绑定](#data-binding) 的格式之一：位于双大括号中的[模板表达式](#template-expression)会被渲染成文本。在被赋值给元素属性或者显示在元素标记中之前，这些文本可能先与周边的文本合并，参见下面的例子。

  code-example(language="html" escape="html").
    <label>My current hero is {{hero.name}}</label>

  :marked
    Learn more about interpolation in the
    [Template Syntax](guide/template-syntax.html#interpolation) chapter.
    
    要学习关于插值表达式的更多知识，参见[模板语法](guide/template-syntax.html#interpolation)一章。

<a id="J"></a>

.l-main-section
<a id="K"></a>
:marked
  ## kebab-case
  ## 烤串命名法
.l-sub-section
  :marked
    The practice of writing compound words or phrases such that each word is separated by a dash or hyphen (-). 
     
    使用中线（-）分隔每个单词来书写复合词或短语的命名方法。
    
    Directive selectors and the root of filenames are often spelled in kebab-case. Examples include: `my-app` and the `hero-list.component.ts`.
    
    指令选择器和文件名等一般都用烤串命名法。比如`my-app`和`hero-list.component.ts`。
    
    This form is also known as [dash-case](#dash-case).
    
    这种格式也叫[中线命名法](#dash-case)。

<a id="L"></a>
.l-main-section
:marked
  ## Lifecycle Hooks
  ## 生命周期钩子
.l-sub-section
  :marked
    [Directives](#directive) and [Components](#component) have a lifecycle
    managed by Angular as it creates, updates and destroys them.
    
    [指令Directives](#directive)和[组件Components](#component)具有生命周期，它们由Angular在创建、更新和销毁它们的过程中进行管理。

    Developers can tap into key moments in that lifecycle by implementing
    one or more of the "Lifecycle Hook" interfaces.
    
    开发者可以通过实现一个或多个“生命周期钩子”接口，切入到生命周期中的关键时间点。

    Each interface has a single hook method whose name is the interface name prefixed with `ng`.
    For example, the `OnInit` interface has a hook method names `ngOnInit`.
    
    每个接口只有一个钩子方法，方法名一般是接口的名字加前缀 `ng`。比如，`OnInit`接口的钩子类的方法名为 `ngOnInit`。

    Angular calls these hook methods in the following order:
    
    Angular会按照下面的顺序调用钩子类方法：
    
    * `ngOnChanges` - called when an [input](#input)/[output](#output) binding values change
    * `ngOnChanges` - 在[输入input](#input)/[输出output](#output)绑定的值变化的时候调用。
    * `ngOnInit` - after the first `ngOnChanges`
    * `ngOnInit` - 在第一个`ngOnChanges`后调用。
    * `ngDoCheck` - developer's custom change detection
    * `ngDoCheck` - 开发者自定义变化监测器。
    * `ngAfterContentInit` - after component content initialized
    * `ngAfterContentInit` - 在组件初始化以后调用。
    * `ngAfterContentChecked` - after every check of component content
    * `ngAfterContentChecked` - 在检查每个组件内容后调用。
    * `ngAfterViewInit` - after component's view(s) are initialized
    * `ngAfterViewInit` - 在组件试图初始化后调用。
    * `ngAfterViewChecked` - after every check of a component's view(s)
    * `ngAfterViewChecked` - 在检查每个组件试图后调用
    * `ngOnDestroy` - just before the directive is destroyed.
    * `ngOnDestroy` - 在指令销毁前调用。

    Learn more in the [Lifecycle Hooks](guide/lifecycle-hooks.html) chapter.
    
    要了解更多，参见[生命周期钩子Lifecycle Hooks](guide/lifecycle-hooks.html)一章。 
// #enddocregion f-l

// #docregion m1
<a id="M"></a>
// #enddocregion m1
// #docregion m2
.l-main-section
:marked
  ## Module
  ## 模块
.l-sub-section
  :marked
    Angular apps are modular.
    
    Angular应用程序是模块化的。
    
    In general, we assemble our application from many modules, both the ones we write ourselves
    and the ones we acquire from others.
    
    一般来说，我们用模块来组装我们的应用程序，这些模块包含我们自己编写的模块和从其它地方获取的模块。

    A typical module is a cohesive block of code dedicated to a single purpose.
    
    典型的模块，是具有单一用途的内聚代码块。

    A module **exports** something of value in that code, typically one thing such as a class.
    A module that needs that thing, **imports** it.
    
    模块一般 **输出** 一个东西：类。
    模块如果需要什么东西，那就 **导入** 它。

    The structure of Angular modules and the import/export syntax
    is based on the [ES2015](#es2015) module standard
    described [here](http://www.2ality.com/2014/09/es6-modules-final.html).
    
    Angular的模块结构和输出/导入语法是基于[ES2015](#es2015)模块化标准的，参见[这里](http://www.2ality.com/2014/09/es6-modules-final.html).

    An application that adheres to this standard requires a module loader to
    load modules on request and resolve inter-module dependencies.
    Angular does not ship with a module loader and does not have a preference
    for any particular 3rd party library (although most samples use SystemJS).
    Application developers may pick any module library that conforms to the standard
    
    采用这个标准的应用程序需要一个模块装载器来按需装载模块并解析模块的依赖关系。Angular不包含任何模块装载器，也不偏爱哪一个第三方库(虽然几乎所有例子都使用SystemJs)。
    应用程序开发者可以自己选择任何与这个标准兼容的模块化库。

    Modules are typically named after the file in which the exported thing is defined.
    The Angular [DatePipe](https://github.com/angular/angular/blob/master/modules/angular2/src/common/pipes/date_pipe.ts)
    class belongs to a feature module named `date_pipe` in the file `date_pipe.ts`.

    模块一般与它用于导出东西的文件同名。比如, Angular的[日期管道DatePipe](https://github.com/angular/angular/blob/master/modules/angular2/src/common/pipes/date_pipe.ts)类属于名叫`date_pipe`的特性模块，位于文件`date_pipe.ts`中。
    
    Developers rarely access Angular feature modules directly.
    We usually import them from one of the Angular [scoped packages](#scoped-package) such as `@angular/core`.

    开发者很少需要直接访问Angular的特性模块。
    我们通常从一个Angular的[**范围化包**](#scoped-package)中导入它们，比如`@angular/core`。

// #enddocregion m2

// #docregion n-s
- var lang = current.path[1]
- var decorator = lang === 'dart' ? 'annotation' : '<a href="#decorator">decorator</a>'
- var decoratorCn = lang === 'dart' ? '注解' : '<a href="#decorator">装饰器</a>'
- var atSym = lang === 'js' ? '' : '@'
<a id="N"></a>
<a id="O"></a>
.l-main-section
:marked
  ## Output
  ## 输出
.l-sub-section
  :marked
    A directive property that can be the ***target*** of an
    [Event Binding](guide/template-syntax.html#property-binding).
    Events stream *out* of this property to the receiver identified
    in the template expression to the right of the equal sign.
    
    输出（Output）是指令的一个属性，它可作为[事件绑定Event Binding](guide/template-syntax.html#property-binding)的 **目标** 。
    事件流可以通过这个属性，流出到接收者（模板表达式等号的右边就是接收者）。
    
    See the [Template Syntax](guide/template-syntax.html#inputs-outputs) chapter.
    
    参见[模板语法Template Syntax](guide/template-syntax.html#inputs-outputs)一章。

.l-main-section
<a id="P"></a>
:marked
  ## PascalCase
  ## Pascal命名法
.l-sub-section
  :marked
    The practice of writing compound words or phrases such that each word or abbreviation begins with a capital letter. 
    Class names are typically spelled in PascalCase. Examples include: `Person` and `Customer`.
    
    遵循“每个单词都用大写开头”的规则的书写复合词或短语的命名方法叫做Pascal命名法。类名一般都采用Pascal命名法。比如`Person`和`Customer`
    
    This form is also known as **upper camel case**, to distinguish it from **lower camel case** which we simply call [camelCase](#camelcase).
    In this documentation, "PascalCase" means *upper camel case* and  "camelCase" means *lower camel case*.
    
    这种命名法也叫**大驼峰式命名法**，以区别于 **小驼峰式命名法”或[驼峰式命名法camelCase](#camelCase)** 。
    在本教程中，“Pascal命名法”都是指的*大驼峰式命名法”，“驼峰式命名法”指的都是“小驼峰式命名法”

:marked
  ## Pipe
  ## 管道
.l-sub-section
  :marked
    An Angular pipe is a function that transforms input values to output values for
    display in a [view](#view). We use the `#{atSym}Pipe` !{decorator}
    to associate the pipe function with a name. We then can use that
    name in our HTML to declaratively transform values on screen.
    
    Angular的管道是一个函数，用于把输入值转换为输出值以供视图[view](#view)显示。我们使用 `#{atSym}Pipe` !{decoratorCn}来把管道函数关联到它的名字上。
    然后，我们可以在HTML中利用它的名字来声明：如何在显示时把输入值转换为输出值。
    
    Here's an example that uses the built-in `currency` pipe to display
    a numeric value in the local currency.
    
    下面这个例子就是用内建的`currency`管道把数字值显示为本地货币格式。

  code-example(language="html" escape="html").
    <label>Price: </label>{{product.price | currency}}
  :marked
    Learn more in the chapter on [pipes](guide/pipes.html) .
    
    要了解更多，参见[管道pipes](guide/pipes.html)一章。

:marked
  ## Provider
.l-sub-section
  :marked
    A Provider creates a new instance of a dependency for the Dependency Injection system.
    It relates a lookup token to code - sometimes called a "recipe" - that can create a dependency value.
    
    依赖注入系统依靠Provider来创建依赖的实例。它把一个查阅用的Token关联到代码（有时也叫“配方”），可以创建依赖值。
    
    For example, `new Provider(Foo, {useClass: Foo})` creates a `Provider`
    that relates the `Foo` token to a function that creates a new instance of the `Foo` class.
    
    比如，`new Provider(Foo, {useClass: Foo})`创建一个`Provider`，把`Foo`Token联系到一个函数，这个函数创建一个`Foo`类的实例。

    There are other ways to create tokens and recipes.
    See [Dependency Injection](#dependency-injection) chapter to learn more.
    
    还有其它一些方法建立Token和方剂。
    参见[依赖注入Dependency Injection](#dependency-injection)以获取更多信息。 

.l-main-section
<a id="Q"></a>
<a id="R"></a>
:marked
  ## Router
  ## 路由器
.l-sub-section
  :marked
    Most applications consist of many screens or [views](#view).
    The user navigates among them by clicking links and buttons
    and taking other similar actions that cause the application to
    replace one view with another.
    
    大部分应用程序包含多个屏或视图[views](#view)。用户通过点击链接、按钮和其它类似动作，在它们之间穿梭，这样应用程序从一个视图变换到另一个视图。

    The Angular [Component Router](guide/router.html) is a richly featured mechanism for configuring
    and managing the entire view navigation process including the creation and destruction
    of views.
    
    Angular的[组件路由器Component Router](guide/router.html)是一个设置和管理整个视图导航过程的特征非常丰富的机制，包括建立和销毁视图。
    
:marked
  ## Routing Component
  ## 路由组件
.l-sub-section
  :marked
    A [Component](#component) with an attached router.

    路由组件是一个附加了路由的[组件Component](#component)。

    In most cases, the component became attached to a [router](#router) by means
    of a `#{atSym}RouterConfig` #{decorator} that defined routes to views controlled by this component.
    
    在大部分情况下，通过`#{atSym}RouterConfig` #{decorator}装饰器，这个组件通常会被附加一个[router路由器](#router)，来定义被这个组件控制的多个视图的路径。

    The component's template has a `RouterOutlet` element where it can display views produced by the router.
    
    组件的模板有一个`路由出口RouterOutlet`元素，用来显示被路由器提供的视图。

    It likely has anchor tags or buttons with `RouterLink` directives that users can click to navigate.
    
    它很大可能还会有一些有`RouterLink`指令的锚标记或按钮，用户可以用来点击导航。

<a id="S"></a>
.l-main-section
:marked
  ## Scoped Package
.l-sub-section
  :marked
    Angular modules are delivered within *scoped packages* such as `@angular/core`, `@angular/common`, `@angular/platform-browser-dynamic`,
    `@angular/http`, and `@angular/router`.

    A [*scoped package*](https://docs.npmjs.com/misc/scope) is a way to group related *npm* packages.
    
    We import a scoped package the same way we'd import a *normal* package. 
    The only difference, from a consumer perspective, 
    is that the package name begins with the Angular *scope name*, `@angular`.
// #enddocregion n-s
+makeExample('../docs/_fragments/architecture/ts/app/app.component.ts', 'import')(format=".")
// #docregion n-s

:marked
  ## Structural Directive
  ## 结构型指令
.l-sub-section
  :marked
    A category of [Directive](#directive) that can
    shape or re-shape HTML layout, typically by adding, removing, or manipulating
    elements and their children.

    一类可以通过添加、删除或操作元素和其子级，来塑造或重塑HTML布局的指令，
    
    The `ngIf` "conditional element" directive and the `ngFor` "repeater" directive are
    good examples in this category.
    
    `ngIf`"有条件的元素conditional element"指令和 `ngFor` "循环器repeater"指令是很好的结构型指令。
    
// #enddocregion n-s

// #docregion t1
<a id="T"></a>
.l-main-section
:marked
  ## Template
  ## 模板
.l-sub-section
  :marked
    A template is a chunk of HTML that Angular uses to render a [view](#view) with
    the support and continuing guidance of an Angular [Directive](#directive),
    most notably a [Component](#component).

    模板是一块HTML。在Angular指令（最典型的 指令[组件Component](#component)）的支持和范围下，Angular用它来渲染试图。
    
    We write templates in a special [Template Syntax](guide/template-syntax.html).
    
    我们使用特殊的[模板语法Template Syntax](guide/template-syntax.html)来编写模板。

:marked
  ## Template Expression
  ## 模板表达式
.l-sub-section
  :marked
    An expression in a JavaScript-like syntax that Angular evaluates within
    a [data binding](#data-binding).  Learn how to write template expressions
    in the [Template Syntax](guide/template-syntax.html#template-expressions) chapter.

    Angular在[数据绑定data binding](#data-binding)内求值的类似JavaScript语法的表达式。在[模板语法Template Syntax](guide/template-syntax.html#template-expressions)章节了解更多模板表达式的知识。
// #enddocregion t1
// #docregion t2
:marked
  ## Transpile
  ## 编译
.l-sub-section
  :marked
    The process of transforming code written in one form of JavaScript
    (e.g., TypeScript) into another form of JavaScript  (e.g., [ES5](#es5)).

    把用JavaScript形式语言（比如TypeScript）编写的程序转换到另一个形式的JavaScript（例如[ES5](#es5))。
 :marked
  ## TypeScript
.l-sub-section
  :marked
    A version of JavaScript that supports most [ECMAScript 2015](#ecmascript=2015)
    language features and many features that may arrive in future versions
    of JavaScript such as [Decorators](#decorator).
    
    一个支持几乎所有[ECMAScript 2015](#ecmascript=2015)语言特性和一些将来版本可能有的特性（比如装饰器[Decorators](#decorator)）的JavaScript语言。

    TypeScript is also noteable for its optional typing system which gives
    us compile-time type-checking and strong tooling support (e.g. "intellisense",
    code completion, refactoring, and intelligent search). Many code editors
    and IDEs support TypeScript either natively or with plugins.
    
    TypeScript同时也以其可选的类型系统出名。该类型系统给我们提供编译时间类型检查和强大的工具支持（比如“Intellisense”， 自动代码补齐，重构和智能搜索等）。许多程序编辑器和开发环境自带TypeScript支持或者通过插件支持。

    TypeScript is the preferred language for Angular 2 development although
    we are welcome to write in other JavaScript dialects such as [ES5](#es5).
    
    TypeScript是Angular 2推荐使用的语言，当然，我们也欢迎使用其它JavaScript语言，比如[ES5](#es5)。

    Angular 2 itself is written in TypeScript.
    
    Angular 2自身是用TypeScript编写的。

    Learn more about TypeScript on its [website](http://www.typescriptlang.org/).
    
    在TypeScript[官方网站](http://www.typescriptlang.org/)了解更多情况。
    
// #enddocregion t2

// #docregion u-z
<a id="U"></a>
<a id="V"></a>
.l-main-section
:marked
  ## View
  ## 视图
.l-sub-section
  :marked
    A view is a portion of the screen that displays information and responds
    to user actions such as clicks, mouse moves, and keystrokes.

    视图是屏幕的一块用于显示信息并回应用户动作，比如点击、移动鼠标和按键等。

    Angular renders a view under the control of one or more [Directives](#directive),
    especially  [Component](#component) directives and their companion [Templates](#template).
    The Component plays such a prominent role that we often
    find it convenient to refer to a component as a view.
    
    Angular在一个或多个[指令](#directive)的控制下渲染视图，尤其是[组件](#component)指令和它配带的[模板](#template)。
    组件扮演非常突出的角色，我们甚至经常为了方便，把组件代替视图来提及。

    Views often contain other views and any view might be loaded and unloaded
    dynamically as the user navigates through the application, typically
    under the control of a [router](#router).
    
    视图一般包含其它视图，任何视图在用户在应用程序中导航的时候，可能被动态加载或卸载，一般[路由器](#router)的控制下进行。

.l-main-section
<a id="W"></a>
<a id="X"></a>
<a id="Y"></a>
<a id="Z"></a>
:marked
  ## Zones
  ## 区域
.l-sub-section
  :marked
    Zones are a mechanism for encapsulating and intercepting
    a JavaScript application's asynchronous activity.
    
    区域是一个封装和截听JavaScript应用程序异步动作的机制。

    The browser DOM and JavaScript have a limited number
    of asynchronous activities, activities such as DOM events (e.g., clicks),
    [promises](#promise), and
    [XHR](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest)
    calls to remote servers.
    
    浏览器DOM和JavaScript之间有一些有限数量的异步活动，比如Dom事件（比如点击）、[契约promises](#promise)、和[XHR](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest)查询远程服务等。

    Zones intercept all of these activities and give a "zone client" the opportunity
    to take action before and after the async activity completes.
    
    区域能截听所有这些活动，并给“区域客户端”机会在异步活动完成之前和之后采取行动。

    Angular runs our application in a zone where it can respond to
    asynchronous events by checking for data changes and updating
    the information it displays via [data binding](#data-binding).
    
    Angular在一个区域内运行我们的应用程序，在这个区域内，它可以对异步事件做出反应，通过检查数据变化、利用数据绑定[data binding](#data-binding)更新信息显示。

    Learn more about zones in this
    [Brian Ford video](https://www.youtube.com/watch?v=3IqtmUscE_U).
    
    在这里学习 [Brian Ford video](https://www.youtube.com/watch?v=3IqtmUscE_U)更多关于区域的知识。
// #enddocregion u-z
