# Upgrading from AngularJS to Angular # 从 AngularJS 升级到 Angular _Angular_ is the name for the Angular of today and tomorrow.
_AngularJS_ is the name for all 1.x versions of Angular. *Angular* 这个名字专指现在和未来的 Angular 版本,而 *AngularJS* 专指 Angular 的所有 1.x 版本。 AngularJS apps are great. Always consider the business case before moving to Angular. An important part of that case is the time and effort to get there. This guide describes the built-in tools for efficiently migrating AngularJS projects over to the Angular platform, a piece at a time. 有很多大型 AngularJS 应用。 在决定迁移到 Angular 之前,首先要深入思考业务案例。 在这些案例中,最重要的部分之一是时间和需要付出的努力。 本章描述用于把 AngularJS 应用高效迁移到 Angular 平台的内置工具,每次讲一点点。 Some applications will be easier to upgrade than others, and there are many ways to make it easier for yourself. It is possible to prepare and align AngularJS applications with Angular even before beginning the upgrade process. These preparation steps are all about making the code more decoupled, more maintainable, and better aligned with modern development tools. That means in addition to making the upgrade easier, you will also improve the existing AngularJS applications. 有些应用可能比其它的升级起来简单,还有一些方法能让把这项工作变得更简单。 即使在正式开始升级过程之前,可以提前准备 AngularJS 的程序,让它向 Angular 看齐。 这些准备步骤几乎都是关于如何让代码更加松耦合、更有可维护性,以及用现代开发工具提高速度的。 这意味着,这种准备工作不仅能让最终的升级变得更简单,而且还能提升 AngularJS 程序的质量。 One of the keys to a successful upgrade is to do it incrementally, by running the two frameworks side by side in the same application, and porting AngularJS components to Angular one by one. This makes it possible to upgrade even large and complex applications without disrupting other business, because the work can be done collaboratively and spread over a period of time. The `upgrade` module in Angular has been designed to make incremental upgrading seamless. 成功升级的关键之一是增量式的实现它,通过在同一个应用中一起运行这两个框架,并且逐个把 AngularJS 的组件迁移到 Angular 中。 这意味着可以在不必打断其它业务的前提下,升级更大、更复杂的应用程序,因为这项工作可以多人协作完成,在一段时间内逐渐铺开。 Angular `upgrade` 模块的设计目标就是让你渐进、无缝的完成升级。 ## Preparation ## 准备工作 There are many ways to structure AngularJS applications. When you begin to upgrade these applications to Angular, some will turn out to be much more easy to work with than others. There are a few key techniques and patterns that you can apply to future proof apps even before you begin the migration. AngularJS 应用程序的组织方式有很多种。当你想把它们升级到 Angular 的时候, 有些做起来会比其它的更容易些。即使在开始升级之前,也有一些关键的技术和模式可以让你将来升级时更轻松。 {@a follow-the-angular-styleguide} ### Follow the AngularJS Style Guide ### 遵循 AngularJS 风格指南 The [AngularJS Style Guide](https://github.com/johnpapa/angular-styleguide/blob/master/a1/README.md) collects patterns and practices that have been proven to result in cleaner and more maintainable AngularJS applications. It contains a wealth of information about how to write and organize AngularJS code - and equally importantly - how **not** to write and organize AngularJS code. [AngularJS 风格指南](https://github.com/johnpapa/angular-styleguide/blob/master/a1/README.md)收集了一些已证明能写出干净且可维护的 AngularJS 程序的模式与实践。 它包含了很多关于如何书写和组织 AngularJS 代码的有价值信息,同样重要的是,**不应该**采用的书写和组织 AngularJS 代码的方式。 Angular is a reimagined version of the best parts of AngularJS. In that sense, its goals are the same as the AngularJS Style Guide's: To preserve the good parts of AngularJS, and to avoid the bad parts. There's a lot more to Angular than just that of course, but this does mean that *following the style guide helps make your AngularJS app more closely aligned with Angular*. Angular 是一个基于 AngularJS 中最好的部分构思出来的版本。在这种意义上,它的目标和 AngularJS 风格指南是一样的: 保留 AngularJS 中好的部分,去掉坏的部分。当然,Angular 还做了更多。 说这些的意思是:*遵循这个风格指南可以让你写出更接近 Angular 程序的 AngularJS 程序*。 There are a few rules in particular that will make it much easier to do *an incremental upgrade* using the Angular `upgrade/static` module: 有一些特别的规则可以让使用 Angular 的 `upgrade/static` 模块进行*增量升级*变得更简单: * The [Rule of 1](https://github.com/johnpapa/angular-styleguide/blob/master/a1/README.md#single-responsibility) states that there should be one component per file. This not only makes components easy to navigate and find, but will also allow us to migrate them between languages and frameworks one at a time. In this example application, each controller, component, service, and filter is in its own source file. [单一规则](https://github.com/johnpapa/angular-styleguide/blob/master/a1/README.md#single-responsibility) 规定每个文件应该只放一个组件。这不仅让组件更容易浏览和查找,而且还让你能逐个迁移它们的语言和框架。 在这个范例程序中,每个控制器、工厂和过滤器都位于各自的源文件中。 * The [Folders-by-Feature Structure](https://github.com/johnpapa/angular-styleguide/blob/master/a1/README.md#folders-by-feature-structure) and [Modularity](https://github.com/johnpapa/angular-styleguide/blob/master/a1/README.md#modularity) rules define similar principles on a higher level of abstraction: Different parts of the application should reside in different directories and NgModules. [按特性分目录的结构](https://github.com/johnpapa/angular-styleguide/blob/master/a1/README.md#folders-by-feature-structure)和[模块化](https://github.com/johnpapa/angular-styleguide/blob/master/a1/README.md#modularity)规则在较高的抽象层定义了一些相似的原则:应用程序中的不同部分应该被分到不同的目录和 Angular 模块中。 When an application is laid out feature per feature in this way, it can also be migrated one feature at a time. For applications that don't already look like this, applying the rules in the AngularJS style guide is a highly recommended preparation step. And this is not just for the sake of the upgrade - it is just solid advice in general! 如果应用程序能用这种方式把每个特性分到一个独立目录中,它也就能每次迁移一个特性。 对于那些还没有这么做的程序,强烈建议把应用这条规则作为准备步骤。而且这也不仅仅对升级有价值, 它还是一个通用的规则,可以让你的程序更“坚实”。 ### Using a Module Loader ### 使用模块加载器 When you break application code down into one component per file, you often end up with a project structure with a large number of relatively small files. This is a much neater way to organize things than a small number of large files, but it doesn't work that well if you have to load all those files to the HTML page with <script> tags. Especially when you also have to maintain those tags in the correct order. That's why it's a good idea to start using a *module loader*. 当你把应用代码分解到每个文件中只放一个组件的粒度后,通常会得到一个由大量相对较小的文件组成的项目结构。 这比组织成少量大文件要整洁得多,但如果你不得不通过 `