anchor.diff:  .l-main-section
   :marked
     ## Appendix: !{_prereq}
  +
  +  ## 附录：node 和 npm
   block install-tooling
     :marked
       Node.js and npm are essential to modern web development with Angular and other platforms.
       Node powers client development and build tools.
       The _npm_ package manager, itself a _node_ application, installs JavaScript libraries.
  +
  +    Node.js 和 npm 对使用 Angular 和其他平台进行现代网络开发的至关重要。
  +    Node 驱动客户端开发和构建工具。
  +    *npm* 包管理器本身是*node*应用，用于安装 JavaScript 库。
       
       <a href="https://docs.npmjs.com/getting-started/installing-node" target="_blank" title="Installing Node.js and updating npm">
       Get them now</a> if they're not already installed on your machine.
  +
  +    如果你的电脑没有安装它们，<a href="https://docs.npmjs.com/getting-started/installing-node" target="_blank" title="安装 Node.js 和更新 npm">
  +    立刻安装它们</a>。
    
       **Verify that you are running node `v4.x.x` or higher and npm `3.x.x` or higher**
       by running the commands `node -v` and `npm -v` in a terminal/console window.
       Older versions produce errors.
   
  +    在终端/控制台窗口运行命令`node -v`和`npm -v`，来**确认你运行的 node 是`v4.x.x`或更高，npm 为`3.x.x`或更高。**。
  +    老版本产品会产生错误。
  +
       We recommend [nvm](https://github.com/creationix/nvm) for managing multiple versions of node and npm. 
       You may need [nvm](https://github.com/creationix/nvm) if you already have projects running on your machine that 
       use other versions of node and npm.
   
  +    我们推荐 [nvm](https://github.com/creationix/nvm) 来管理多版本 node 和 npm。
  +    如果你的电脑上已经有使用其他版本 node 和 npm 的项目，你可能需要[nvm](https://github.com/creationix/nvm)。
  +
   +ifDocsFor('ts')
     a#why-locally
     .l-main-section
     :marked
       ## Appendix: Why develop locally
   
  +    ## 附录：为何在本地开发
  +
       <live-example>Live coding</live-example> in the browser is a great way to explore Angular.
  +
  +    在浏览器中<live-example>在线编程</live-example>是很好的探索 Angular 的方法。
   
       Links on almost every documentation page open completed samples in the browser.
       You can play with the sample code, share your changes with friends, and download and run the code on your own machine.
  +
  +    几乎每章文档里面的链接都在浏览器中打开完整的例子。
  +    你可以用这些代码做实验，或者与朋友共享你的修改，或者下载并在你自己的电脑上运行这些代码。
   
       The [QuickStart](../quickstart.html "Angular QuickStart Playground") shows just the `AppComponent` file.
       It creates the equivalent of `app.module.ts` and `main.ts` internally _for the playground only_.
       so the reader can discover Angular without distraction.
  -    The other samples are based on the QuickStart seed. 
  +    The other samples are based on the QuickStart seed.
  +
  +    [快速起步](../quickstart.html "Angular 快速起步游乐场")仅仅展示了`AppComponent`文件。
  +    它在内部创建了只为*游乐场*而准备的等价`app.module.ts`和`main.ts`。
  +    所以读者可以在零干扰的情况下探索 Angular。
  +    其他例子是基于 《快速起步》种子的。
   
       As much fun as this is ...
  +
  +    虽然有这么多的乐趣，但是...
  +
       * you can't ship your app in plunker
  +
  +    * 你不能在 plunker 里面发布你的应用
  +
       * you aren't always online when writing code
  +
  +    * 编程时你不可能总是在线
  +
       * transpiling TypeScript in the browser is slow
  +
  +    * 在浏览器中编译 TypeScript 很慢
  +
       * the type support, refactoring, and code completion only work in your local IDE
  +
  +    * 只有本地IDE有类型支持、代码重构和代码自动完成
   
       Use the <live-example><i>live coding</i></live-example> environment as a _playground_, 
       a place to try the documentation samples and experiment on your own.
       It's the perfect place to reproduce a bug when you want to
       <a href="https://github.com/angular/angular.io/issues/new" target="_blank" title="File a documentation issue">file a documentation issue</a> or
       <a href="https://github.com/angular/angular/issues/new" target="_blank" title="File an Angular issue">file an issue with Angular itself</a>.
  +
  +    把<live-example><i>在线编程</i></live-example>环境当做*游乐场*，一个尝试文档例子和自己做实验的地方。
  +    当你想要<a href="https://github.com/angular/angular.io/issues/new" target="_blank" title="提交关于文档的问题">提交关于文档的问题</a>或者
  +    <a href="https://github.com/angular/angular/issues/new" target="_blank" title="提交关于 Angular 的问题">提交关于 Angular 自身的问题</a>时，
  +    它是重现错误的完美地方。
     
       For real development, we strongly recommend [developing locally](#develop-locally).
  +
  +    对于现实项目开发，我们强烈推荐在[本地开发](#develop-locally)。
  
positive.code:         Defines `AppModule`, the [root module](appmodule.html "AppModule: the root module") that tells Angular how to assemble the application.
          Right now it declares only the `AppComponent`. 
          Soon there will be more components to declare. 
    tr
      td <ngio-ex>main.ts</ngio-ex>
      td
  
negative.code:         Defines the same `AppComponent` as the one in the QuickStart !{_playground}.
          It is the **root** component of what will become a tree of nested components
          as the application evolves. 
  
          定义与《快速起步》游乐场同样的`AppComponent`。
          它是**根**组件，随着应用的演变，它将变成一颗嵌套组件树。
    tr(if-docs="ts")
      td <code>app.module.ts</code>
      td
  