angular-cn/public/docs/ts/latest/guide/upgrade.jade

include ../_util-fns

:marked
  Having an existing Angular 1 application doesn't mean that we can't
  begin enjoying everything Angular 2 has to offer. That's because Angular 2
  comes with built-in tools for migrating Angular 1 projects over to the
  Angular 2 platform.

  Some applications will be easier to upgrade than others, and there are
  ways in which we can make it easier for ourselves. It is possible to
  prepare and align Angular 1 applications with Angular 2 even before beginning
  the upgrade process. These preparation steps are all about making the code
  more decoupled, more maintainable, and up to speed with modern development
  tools. That means the preparation work will not only make the eventual upgrade
  easier, but will also generally improve our Angular 1 applications.

  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 Angular 1 components to Angular 2 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 2 has been designed to
  make incremental upgrading seamless.

  1. [Preparation](#preparation)
      1. [Following The Angular Style Guide](#following-the-angular-style-guide)
      2. [Using a Module Loader](#using-a-module-loader)
      3. [Migrating to TypeScript](#migrating-to-typescript)
      4. [Using Component Directives](#using-component-directives)
  2. [Upgrading with The Upgrade Adapter](#upgrading-with-the-upgrade-adapter)
      1. [How The Upgrade Adapter Works](#how-the-upgrade-adapter-works)
      2. [Bootstrapping Hybrid Angular 1+2 Applications](#bootstrapping-hybrid-angular-1-2-applications)
      3. [Using Angular 2 Components from Angular 1 Code](#using-angular-2-components-from-angular-1-code)
      4. [Using Angular 1 Component Directives from Angular 2 Code](#using-angular-1-component-directives-from-angular-2-code)
      5. [Projecting Angular 1 Content into Angular 2 Components](#projecting-angular-1-content-into-angular-2-components)
      6. [Transcluding Angular 2 Content into Angular 1 Component Directives](#transcluding-angular-2-content-into-angular-1-component-directives)
      7. [Making Angular 1 Dependencies Injectable to Angular 2](#making-angular-1-dependencies-injectable-to-angular-2)
      8. [Making Angular 2 Dependencies Injectable to Angular 1](#making-angular-2-dependencies-injectable-to-angular-1)
  3. [PhoneCat Preparation Tutorial](#phonecat-preparation-tutorial)
      1. [Switching to TypeScript And Module Loading](#switching-to-typescript-and-module-loading)
      2. [Preparing Unit and E2E Tests](#preparing-unit-and-e2e-tests)
      3. [Enjoying The Benefits of TypeScript](#enjoying-the-benefits-of-typescript)

  4. [PhoneCat Upgrade Tutorial](#phonecat-upgrade-tutorial)
      1. [Bootstrapping A Hybrid 1+2 PhoneCat](#bootstrapping-a-hybrid-1-2-phonecat)
      2. [Upgrading the Phone factory](#upgrading-the-phone-factory)
      3. [Upgrading Controllers to Components](#upgrading-controllers-to-components)
      4. [Switching To The Angular 2 Router And Bootstrap](#switching-to-the-angular-2-router-and-bootstrap)
      5. [Saying Goodbye to Angular 1](#saying-goodbye-to-angular-1)

.l-main-section
:marked
  # Preparation
  
  There are many ways to structure Angular 1 applications. When we begin
  to upgrade these applications to Angular 2, some will turn out to be
  much more easy to work with than others. There are a few key techniques
  and patterns that we can apply to future proof our apps even before we
  begin the migration.

  ## Following The Angular Style Guide

  The [Angular Style Guide](https://github.com/johnpapa/angular-styleguide)
  collects patterns and practices that have been proven to result in
  cleaner and more maintainable Angular 1 applications. It contains a wealth
  of information about how to write and organize Angular code - and equally
  importantly - how **not** to write and organize Angular code.

  Angular 2 is a reimagined version of the best parts of Angular 1. In that
  sense, its goals are the same as the Angular Style Guide's: To preserve
  the good parts of Angular 1, and to avoid the bad parts. There's a lot
  more to Angular 2 than just that of course, but this does mean that
  *following the style guide helps make your Angular 1 app more closely
  aligned with Angular 2*.

  There are a few rules in particular that will make it much easier to do
  *an incremental upgrade* using the Angular 2 `upgrade` module:

  * 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, factory, and filter is in its own source file.
  * 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 Angular modules.
    
  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 Angular 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!

  ## Using a Module Loader
  
  When we break application code down into one component per file, we 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*.
  
  Using a module loader such as [SystemJS](https://github.com/systemjs/systemjs),
  [Webpack](http://webpack.github.io/), or [Browserify](http://browserify.org/)
  allows us to use the built-in module systems of the TypeScript or ES2015 languages in our apps.
  We can use the `import` and `export` features that explicitly specify what code can
  and will be shared between different parts of the application. For ES5 applications
  we can use CommonJS style `require` and `module.exports` features. In both cases,
  the module loader will then take care of loading all the code the application needs
  in the correct order.

  When we then take our applications into production, module loaders also make it easier
  to package them all up into production bundles with batteries included.

:marked
  ## Migrating to TypeScript

  If part of our Angular 2 upgrade plan is to also take TypeScript into use, it makes
  sense to bring in the TypeScript compiler even before the upgrade itself begins.
  This means there's one less thing to learn and think about during the actual upgrade.
  It also means we can start using TypeScript features in our Angular 1 code.

  Since TypeScript is a superset of ECMAScript 2015, which in turn is a superset
  of ECMAScript 5, "switching" to TypeScript doesn't necessarily require anything
  more than installing the TypeScript compiler and switching renaming files from
  `*.js` to `*.ts`. But just doing that is not hugely useful or exciting, of course.
  Additional steps like the following can give us much more bang for the buck:

  * For applications that use a module loader, TypeScript imports and exports
    (which are really ECMAScript 2015 imports and exports) can be used to organize
    code into modules.
  * Type annotations can be gradually added to existing functions and variables
    to pin down their types and get benefits like build-time error checking,
    great autocompletion support and inline documentation.
  * JavaScript features new to ES2015, like `let`s and `const`s, default function
    parameters, and destructuring assignments can also be gradually added to make
    the code more expressive.
  * Services and controllers can be turned into *classes*. That way they'll be a step
    closer to becoming Angular 2 service and component classes, which will make our
    life easier once we do the upgrade.
    
  ## Using Component Directives

  In Angular 2, components are the main primitive from which user interfaces
  are built. We define the different parts of our UIs as components, and then
  compose the UI by using components in our templates.
  
  You can also do this in Angular 1, using *component directives*. These are
  directives that define their own templates, controllers, and input/output bindings -
  the same things that Angular 2 components define. Applications built with
  component directives are much easier to migrate to Angular 2 than applications
  built with lower-level features like `ng-controller`,  `ng-include`, and scope
  inheritance.
  
  To be Angular 2 compatible, an Angular 1 component directive should configure
  these attributes:
  
  * `restrict: 'E'`. Components are usually used as elements.
  * `scope: {}` - an isolate scope. In Angular 2, components are always isolated
    from their surroundings, and we should do this in Angular 1 too.
  * `bindToController: {}`. Component inputs and outputs should be bound
    to the controller instead of using the `$scope`. 
  * `controller` and `controllerAs`. Components have their own controllers.
  * `template` or `templateUrl`. Components have their own templates.
  
  Component directives may also use the following attributes:
  
  * `transclude: true`, if the component needs to transclude content from elsewhere.
  * `require`, if the component needs to communicate with some parent component's
    controller.
    
  Component directives **may not** use the following attributes:
  
  * `compile`. This will not be supported in Angular 2.
  * `replace: true`. Angular 2 never replaces a component element with the
    component template. This attribute is also deprecated in Angular 1.
  * `priority` and `terminal`. While Angular 1 components may use these,
    they are not used in Angular 2 and it is better not to write code
    that relies on them.
    
  An Angular 1 component directive that is fully aligned with the Angular 2
  architecture may look something like this:
    
+makeExample('upgrade-adapter/ts/app/hero-detail.directive.ts')

:marked
  Angular 1.5 introduces the [component API](https://docs.angularjs.org/api/ng/type/angular.Module)
  that makes it easier to define directives like these. It is a good idea to use
  this API for component directives for several reasons:
  
  * It requires less boilerplate code.
  * It enforces the use of component best practices like `controllerAs`.
  * It has good default values for directive attributes like `scope`,
    `restrict`, and `transclude`.
    
  The component directive example from above looks like this when expressed
  using the component API:
  
+makeExample('upgrade-adapter/ts/app/upgrade-io/hero-detail.component.ts')



.l-main-section
:marked
  # Upgrading with The Upgrade Adapter
  
  The `upgrade` module in Angular 2 is a very useful tool for upgrading
  anything but the smallest of applications. With it we can mix and match
  Angular 1 and 2 components in the same application and have them interoperate
  seamlessly. That means we don't have to do the upgrade work all at once,
  since there's a natural coexistence between the two frameworks during the
  transition period.

  ## How The Upgrade Adapter Works

  The primary tool provided by the upgrade module is called the `UpgradeAdapter`.
  This is a service that can bootstrap and manage hybrid applications that support
  both Angular 2 and Angular 1 code.

  When we use `UpgradeAdapter`, what we're really doing is *running both versions
  of Angular at the same time*. All Angular 2 code is running in the Angular 2
  framework, and Angular 1 code in the Angular 1 framework. Both of these are the
  actual, fully featured versions of the frameworks. There is no emulation going on,
  so we can expect to have all the features and natural behavior of both frameworks.

  What happens on top of this is that components and services managed by one
  framework can interoperate with those from the other framework. This happens
  in three main areas: Dependency injection, the DOM, and change detection.
  
  ### Dependency Injection

  Dependency injection is front and center in both Angular 1 and
  Angular 2, but there are some key differences between the two
  frameworks in how it actually works.

table
  tr
    th Angular 1
    th Angular 2
  tr
    td
      :marked
        Dependency injection tokens are always strings
    td
      :marked
        Tokens [can have different types](../guide/dependency-injection.html).
        They are often classes. They may also be strings.
  tr
    td
      :marked
        There is exactly one injector. Even in multi-module applications,
        everything is poured into one big namespace.
    td
      :marked
        There is a [tree hierarchy of injectors](../guide/hierarchical-dependency-injection.html),
        with a root injector and an additional injector for each component.
    
:marked
  Even accounting for these differences we can still have dependency injection
  interoperability. The `UpgradeAdapter` resolves the differences and makes
  everything work seamlessly:

  * We can make Angular 1 services available for injection to Angular 2 code
    by *upgrading* them. The same singleton instance of each service is shared
    between the frameworks. In Angular 2 these services will always be in the
    *root injector* and available to all components. They will always have
    *string tokens* - the same tokens that they have in Angular 1.
  * We can also make Angular 2 services available for injection to Angular 1 code
    by *downgrading* them. Only services from the Angular 2 root injector can
    be downgraded. Again, the same singleton instances are shared between the frameworks.
    When we register a downgrade, we explicitly specify a *string token* that we want to
    use in Angular 1.
  
figure.image-display
  img(src="/resources/images/devguide/upgrade/injectors.png" alt="The two injectors in a hybrid application" width="700")

:marked
  ### Components and the DOM

  What we'll find in the DOM of a hybrid application are components and
  directives from both Angular 1 and Angular 2. These components
  communicate with each other by using the input and output bindings
  of their respective frameworks, which the `UpgradeAdapter` bridges
  together. They may also communicate through shared injected dependencies,
  as described above.

  There are two key things to understand about what happens in the DOM
  of a hybrid application:

  1. Every element in the DOM is owned by exactly one of the two
     frameworks. The other framework ignores it. If an element is
     owned by Angular 1, Angular 2 treats it as if it didn't exist,
     and vice versa.
  2. The root of the application *is always an Angular 1 template*.

  So a hybrid application begins life as an Angular 1 application,
  and it is Angular 1 that processes its root template. Angular 2 then steps
  into the picture when an Angular 2 component is used somewhere in
  the application templates. That component's view will then be managed
  by Angular 2, and it may use any number of Angular 2 components and
  directives.

  Beyond that, we may interleave the two frameworks as much as we need to.
  We always cross the boundary between the two frameworks by one of two
  ways:

  1. By using a component from the other framework: An Angular 1 template
     using an Angular 2 component, or an Angular 2 template using an
     Angular 1 component.
  2. By transcluding or projecting content from the other framework. The
    `UpgradeAdapter` bridges the related concepts of  Angular 1 transclusion
     and Angular 2 content projection together.

figure.image-display
 img(src="/resources/images/devguide/upgrade/dom.png" alt="DOM element ownership in a hybrid application" width="500")

:marked
  Whenever we use a component that belongs to the other framework, a
  switch between framework boundaries occurs. However, that switch only
  happens to the *children* of the component element. Consider a situation
  where we use an Angular 2 component from Angular 1 like this:

  ```
  <ng2-component></ng2-component>
  ```

  The DOM element `<ng2-component>` will remain to be an Angular 1 managed
  element, because it's defined in an Angular 1 template. That also
  means you can apply additional Angular 1 directives to it, but *not*
  Angular 2 directives. It is only in the template of the `Ng2Component`
  component where Angular 2 steps in. This same rule also applies when you
  use Angular 1 component directives from Angular 2.
  
:marked
  ### Change Detection

  Change detection in Angular 1 is all about `scope.$apply()`. After every
  event that occurs, `scope.$apply()` gets called. This is done either
  automatically by the framework, or in some cases manually by our own
  code. It is the point in time when change detection occurs and data
  bindings get updated.

  In Angular 2 things are different. While change detection still
  occurs after every event, no one needs to call `scope.$apply()` for
  that to happen. This is because all Angular 2 code runs inside something
  called the [Angular zone](../api/core/NgZone-class.html). Angular always
  knows when the code finishes, so it also knows when it should kick off
  change detection. The code itself doesn't have to call `scope.$apply()`
  or anything like it.

  In the case of hybrid applications, the `UpgradeAdapter` bridges the
  Angular 1 and Angular 2 approaches. Here's what happens:

  * Everything that happens in the application runs inside the Angular 2 zone.
    This is true whether the event originated in Angular 1 or Angular 2 code.
    The zone triggers Angular 2 change detection after every event.
  * The `UpgradeAdapter` will invoke the Angular 1 `$rootScope.$apply()` after
    every turn of the Angular zone. This also triggers Angular 1 change
    detection after every event.
    
figure.image-display
  img(src="/resources/images/devguide/upgrade/change_detection.png" alt="Change detection in a hybrid application" width="600")

:marked
  What this means in practice is that we do not need to call `$apply()` in
  our code, regardless of whether it is in Angular 1 on Angular 2. The
  `UpgradeAdapter` does it for us. We *can* still call `$apply()` so there
  is no need to remove such calls from existing code. Those calls just don't
  have any effect in a hybrid application.

  
:marked
  When we downgrade an Angular 2 component and then use it from Angular 1,
  the component's inputs will be watched using Angular 1 change detection.
  When those inputs change, the corresponding properties in the component
  are set. We can also hook into the changes by implementing the
  [OnChanges](../api/core/OnChanges-interface.html) interface in the component,
  just like we could if it hadn't been downgraded.

  Correspondingly, when we upgrade an Angular 1 component and use it from Angular 2,
  all the bindings defined for the component directive's `scope` (or `bindToController`)
  will be hooked into Angular 2 change detection. They will be treated
  as regular Angular 2 inputs and set onto the scope (or controller) when
  they change.

  ## Bootstrapping Hybrid Angular 1+2 Applications

  The first step to upgrading an application using the `UpgradeAdapter` is
  always to bootstrap it as a hybrid that supports both Angular 1 and
  Angular 2.

  Pure Angular 1 applications can be bootstrapped in two ways: By using an `ng-app`
  directive somewhere on the HTML page, or by calling
  [angular.bootstrap](https://docs.angularjs.org/api/ng/function/angular.bootstrap)
  from JavaScript. In Angular 2, only the second method is possible - there is
  no `ng-app` in Angular 2. This is also the case for hybrid applications.
  Therefore, it is a good preliminary step to switch Angular 1 applications to use the
  JavaScript bootstrap method even before switching them to hybrid mode.

  Say we have an `ng-app` driven bootstrap such as this one:
  
+makeExample('upgrade-adapter/ts/index-ng-app.html', null, null, {otl: /(ng-app.*ng-strict-di)/})

:marked
  We can remove the `ng-app` and `ng-strict-di` directives from the HTML
  and instead switch to calling `angular.bootstrap` from JavaScript, which
  will result in the same thing:

+makeExample('upgrade-adapter/ts/app/1-bootstrap/app.module.ts', 'bootstrap')

:marked
  To then switch the application into hybrid mode, we must first
  install Angular 2 to the project. Follow the instructions in
  [the QuickStart](../quickstart.html) for some pointers on this.
  When we have Angular 2 installed, we can import and instantiate
  the `UpgradeAdapter`, and then call its `bootstrap` method. It
  is designed to take the exact same arguments as
  [angular.bootstrap](https://docs.angularjs.org/api/ng/function/angular.bootstrap)
  so that it is easy to make the switch:

+makeExample('upgrade-adapter/ts/app/1-2-hybrid-bootstrap/app.module.ts', 'bootstrap')

:marked
  At this point we'll be running a hybrid Angular 1+2 application! All the
  existing Angular 1 code will work as it always did, but we are now ready
  to run Angular 2 code as well.

.alert.is-helpful
  :marked
    One notable difference between `angular.bootstrap` and
    `upgradeAdapter.bootstrap` is that the latter works *asynchronously*.
    This means that we cannot assume that the application has been instantiated
    immediately after the bootstrap call returns.
    
:marked
  As we begin to migrate components to Angular 2, we'll be using the
  `UpgradeAdapter` for more than just bootstrapping. It'll be important
  to use the **same** instance of the adapter across the whole application,
  because it stores internal information about what's going on in the application.
  It'll be useful to have a module for a shared `UpgradeAdapter` instance in
  the project:
  
+makeExample('upgrade-adapter/ts/app/1-2-hybrid-shared-adapter-bootstrap/upgrade_adapter.ts', null, 'upgrade_adapter.ts')

:marked
  This shared instance can then be pulled in to all the modules that need it:
  
+makeExample('upgrade-adapter/ts/app/1-2-hybrid-shared-adapter-bootstrap/app.module.ts', 'bootstrap')

:marked
  ## Using Angular 2 Components from Angular 1 Code
figure
  img(src="/resources/images/devguide/upgrade/a1-to-a2.png" alt="Using an Angular 2 component from Angular 1 code" align="left" style="width:250px; margin-left:-40px;margin-right:10px" )
:marked
  Once we're running a hybrid app, we can start the gradual process of upgrading
  code. One of the more common patterns for doing that is to use an Angular 2 component
  in an Angular 1 context. This could be a completely new component or one that was
  previously Angular 1 but has been rewritten for Angular 2.
  
  Say we have a simple Angular 2 component that shows information about a hero:
  
+makeExample('upgrade-adapter/ts/app/downgrade-static/hero-detail.component.ts', null, 'hero-detail.component.ts')

:marked
  If we want to use this component from Angular 1, we need to *downgrade* it
  using the upgrade adapter. What we get when we do that is an Angular 1
  *directive*, which we can then register into our Angular 1 module:
  
+makeExample('upgrade-adapter/ts/app/downgrade-static/app.module.ts', 'downgradecomponent')

:marked
  What we have here is an Angular 1 directive called `heroDetail`, which we can
  use like any other directive in our Angular 1 templates. 
  
+makeExample('upgrade-adapter/ts/index-downgrade-static.html', 'usecomponent')

.alert.is-helpful
  :marked
    Note that since Angular 1 directives are matched based on their name,
    *the selector metadata of the Angular 2 component is not used in Angular 1*.
    It is matched as an element directive (`restrict: 'E'`) called `heroDetail`.

:marked
  Most components are not quite this simple, of course. Many of them
  have *inputs and outputs* that connect them to the outside world. An
  Angular 2 hero detail component with inputs and outputs might look
  like this:
   
+makeExample('upgrade-adapter/ts/app/downgrade-io/hero-detail.component.ts', null, 'hero-detail.component.ts')

:marked
  These inputs and outputs can be supplied from the Angular 1 template, and the
  `UpgradeAdapter` takes care of bridging them over:
  
+makeExample('upgrade-adapter/ts/index-downgrade-io.html', 'usecomponent')

:marked
  Note that even though we are in an Angular 1 template, **we're using Angular 2
  attribute syntax to bind the inputs and outputs**. This is a requirement for downgraded
  components. The expressions themselves are still regular Angular 1 expressions.

  The `$event` variable can be used in outputs to gain access to the
  object that was emitted. In this case it will be the `Hero` object, because
  that is what was passed to `this.deleted.emit()`.
  
  Since this is an Angular 1 template, we can still use other Angular 1
  directives on the element, even though it has Angular 2 binding attributes on it.
  For  example, we can easily make multiple copies of the component using `ng-repeat`:
  
+makeExample('upgrade-adapter/ts/index-downgrade-io.html', 'userepeatedcomponent')

:marked
  ## Using Angular 1 Component Directives from Angular 2 Code
figure
  img(src="/resources/images/devguide/upgrade/a2-to-a1.png" alt="Using an Angular 1 component from Angular 2 code" align="left" style="width:250px; margin-left:-40px;margin-right:10px" )
:marked
  So, we can write an Angular 2 component and then use it from Angular 1
  code. This is very useful when we start our migration from lower-level
  components and work our way up. But in some cases it is more convenient
  to do things in the opposite order: To start with higher-level components
  and work our way down. This too can be done using the `UpgradeAdapter`.
  We can *upgrade* Angular 1 component directives and then use them from
  Angular 2.
  
  Not all kinds of Angular 1 directives can be upgraded. The directive
  really has to be a *component directive*, with the characteristics
  [described in the preparation guide above](#using-component-directives).
  Our safest bet for ensuring compatibility is using the
  [component API](https://docs.angularjs.org/api/ng/type/angular.Module) 
  introduced in Angular 1.5.
  
  A simple example of an upgradable component is one that just has a template
  and a controller: 
   
+makeExample('upgrade-adapter/ts/app/upgrade-static/hero-detail.component.ts', null, 'hero-detail.component.ts')

:marked
  We can *upgrade* this component to Angular 2 using the `UpgradeAdapter`'s
  `upgradeNg1Component` method. It takes the name of an Angular 1 component
  directive and returns an Angular 2 **component class**. When we then
  want to use it from an Angular 2 component, we list it the in the `directives`
  metadata of the component and then just use it in the Angular 2 template:
  
+makeExample('upgrade-adapter/ts/app/upgrade-static/container.component.ts', null, 'container.component.ts')

.alert.is-helpful
  :marked
    Upgraded components always have an element selector, which is based
    on the original name of the original Angular 1 component directive.


:marked
  An upgraded component may also have inputs and outputs, as defined by
  the scope/controller bindings of the original Angular 1 component
  directive. When we use the component from an Angular 2 template,
  we provide the inputs and outputs using **Angular 2 template syntax**,
  with the following rules:
  
table
  tr
    th
    th Binding definition
    th Template syntax
  tr
    th Attribute binding
    td
      :marked
        `myAttribute: '@myAttribute'`
    td
      :marked
        `<my-component myAttribute="value">`
  tr
    th Expression binding
    td
      :marked
        `myOutput: '&myOutput'`
    td
      :marked
        `<my-component (myOutput)="action()">`
  tr
    th Two-way binding
    td
      :marked
        `myValue: '=myValue'`
    td
      :marked
        As input: `<my-component [myValue]="anExpression">` or
        as two-way binding: `<my-component [(myValue)]="anExpression"`

:marked
  As an example, say we have a hero detail Angular 1 component directive
  with one input and one output:
  
+makeExample('upgrade-adapter/ts/app/upgrade-io/hero-detail.component.ts', null, 'hero-detail.component.ts')

:marked
  We can upgrade this component to Angular 2, and then provide the input
  and output using Angular 2 template syntax:
  
+makeExample('upgrade-adapter/ts/app/upgrade-io/container.component.ts', null, 'container.component.ts')


:marked
  ## Projecting Angular 1 Content into Angular 2 Components
figure
  img(src="/resources/images/devguide/upgrade/a1-to-a2-with-projection.png" alt="Projecting Angular 1 content into Angular 2" align="left" style="width:250px; margin-left:-40px;margin-right:10px" )
:marked
  When we are using a downgraded Angular 2 component from an Angular 1
  template, the need may arise to *transclude* some content into it. This
  is also possible. While there is no such thing as transclusion in Angular 2,
  there is a very similar concept called *content projection*. The `UpgradeAdapter`
  is able to make these two features interoperate.
  
  Angular 2 components that support content projection make use of an `<ng-content>`
  tag within them. Here's an example of such a component:
  
+makeExample('upgrade-adapter/ts/app/1-to-2-projection/hero-detail.component.ts', null, 'hero-detail.component.ts')

:marked
  When using the component from Angular 1, we can supply contents for it. Just
  like they would be transcluded in Angular 1, they get projected to the location
  of the `<ng-content>` tag in Angular 2:
  
+makeExample('upgrade-adapter/ts/index-1-to-2-projection.html', 'usecomponent')

.alert.is-helpful
  :marked
    When Angular 1 content gets projected inside an Angular 2 component, it still
    remains in "Angular 1 land" and is managed by the Angular 1 framework.
    
:marked
  ## Transcluding Angular 2 Content into Angular 1 Component Directives
figure
  img(src="/resources/images/devguide/upgrade/a2-to-a1-with-transclusion.png" alt="Projecting Angular 2 content into Angular 1" align="left" style="width:250px; margin-left:-40px;margin-right:10px" )
:marked
  Just like we can project Angular 1 content into Angular 2 components,
  we can *transclude* Angular 2 content into Angular 1 components, whenever
  we are using upgraded versions from them.
  
  When an Angular 1 component directive supports transclusion, it may use
  the `ng-transclude` directive in its template to mark the transclusion
  point:
  
+makeExample('upgrade-adapter/ts/app/2-to-1-transclusion/hero-detail.component.ts', null, 'hero-detail.component.ts')

.alert.is-helpful
  :marked
    The directive also needs to have the `transclude: true` option enabled.
    It is on by default for component directives defined with the
    1.5 component API.
    
:marked
  If we upgrade this component and use it from Angular 2, we can populate
  the component tag with contents that will then get transcluded:
  
+makeExample('upgrade-adapter/ts/app/2-to-1-transclusion/container.component.ts', null, 'container.component.ts')

:marked
  ## Making Angular 1 Dependencies Injectable to Angular 2
  
  When running a hybrid app, we may bump into situations where we need to have
  some Angular 1 dependencies to be injected to Angular 2 code. This may be
  because we have some business logic still in Angular 1 services, or because
  we need some of Angular 1's built-in services like `$location` or `$timeout`.
  
  In these situations, it is possible to *upgrade* an Angular 1 provider to
  Angular 2. This makes it possible to then inject it somewhere in Angular 2
  code. For example, we might have a service called `HeroesService` in Angular 1:
  
+makeExample('upgrade-adapter/ts/app/1-to-2-providers/heroes.service.ts', null, 'heroes.service.ts')

:marked
  We can upgrade the service using the `UpgradeAdapter`'s `upgradeNg1Provider` method
  by giving it the name of the service. This adds the service into Angular 2's root injector.
  
+makeExample('upgrade-adapter/ts/app/1-to-2-providers/app.module.ts', 'register', 'app.module.ts')

:marked
  We can then inject it in Angular 2 using a string token that matches
  its original name in Angular 1:
  
+makeExample('upgrade-adapter/ts/app/1-to-2-providers/hero-detail.component.ts', null, 'hero-detail.component.ts')

.alert.is-helpful
  :marked
    In this example we upgraded a service class, which has the added benefit that
    we can use a TypeScript type annotation when we inject it. While it doesn't
    affect how the dependency is handled, it enables the benefits of static type
    checking. This is not required though, and any Angular 1 service, factory, or
    provider can be upgraded.
  
:marked
  ## Making Angular 2 Dependencies Injectable to Angular 1

  In addition to upgrading Angular 1 dependencies, we can also *downgrade* 
  Angular 2 dependencies, so that we can use them from Angular 1. This can be
  useful when we start migrating services to Angular 2 or creating new services
  in Angular 2 while we still have components written in Angular 1.
  
  For example, we might have an Angular 2 service called `Heroes`:
  
+makeExample('upgrade-adapter/ts/app/2-to-1-providers/heroes.ts', null, 'heroes.ts')

:marked
  We can again use the `UpgradeAdapter` for this, but first we need to register `Heroes`
  to the Angular 2 injector itself. In a pure Angular 2 application we would do this
  when we bootstrap the app, as described in the [dependency injection guide](dependency-injection.html#!#providers).
  But since hybrid applications are bootstrapped using the `UpgradeAdapter`, we also
  need to register our Angular 2 providers using `UpgradeAdapter`. It has a method
  called `addProvider` for this purpose.
  
  Once we've registered the Angular 2 provider, we can turn `Heroes` into an *Angular 1
  factory function* using `upgradeAdapter.downgradeNg2Provider()`. We can
  then plug the factory into an Angular 1 module, at which point we also choose what the
  name of the dependency will be in Angular 1:
  
+makeExample('upgrade-adapter/ts/app/2-to-1-providers/app.module.ts', 'register', 'app.module.ts')

:marked
  After this, the service is injectable anywhere in our Angular 1 code:
  
+makeExample('upgrade-adapter/ts/app/2-to-1-providers/hero-detail.component.ts', null, 'hero-detail.component.ts')

.l-main-section
:marked
  # PhoneCat Preparation Tutorial

  In this section and the one following it we will look at a complete example of
  preparing and upgrading an application using the `upgrade` module. The app
  we're going to work on is [Angular PhoneCat](https://github.com/angular/angular-phonecat)
  from [the original Angular 1 tutorial](https://docs.angularjs.org/tutorial),
  which is where many of us began our Angular adventures. Now we'll see how to
  bring that application to the brave new world of Angular 2.
  
  During the process we'll learn how to apply the steps outlined in the 
  [preparation guide](#preparation) in practice: We'll align the application
  with Angular 2 and also take both the SystemJS module loader and TypeScript
  into use.

  To follow along with the tutorial, clone the
  [angular-phonecat](https://github.com/angular/angular-phonecat) repository
  and apply the steps as we go
  
.alert.is-important
  :marked
    If you do clone this repository, note that it doesn't look like this guide
    assumes yet. There's [a pull request](https://github.com/angular/angular-phonecat/pull/289)
    that will change this. Meanwhile, you'll find a good starting point from
    [this commit](https://github.com/teropa/angular-phonecat/commit/d6fb83e1c2db9d1812c7c478fdb8d92301ef0061).
  
:marked
  In terms of project structure, this is where our work begins
  
.filetree
  .file angular-phonecat
  .children
    .file bower.json
    .file package.json
    .file app
    .children
      .file js
      .children
        .file core
        .children
          .file checkmark.filter.js
          .file core.module.js
          .file phone.factory.js
        .file phone_detail
        .children
          .file phone_detail.html
          .file phone_detail.module.js
          .file phone_detail.controller.js
        .file phone_list
        .children
          .file phone_list.html
          .file phone_list.module.js
          .file phone_list.controller.js
        .file app.module.js
      .file css
      .children
        .file animations.css
        .file app.css
      .file img
      .children
        .file  ...
      .file phones
      .children
        .file  ...
      .file index.html
    .file test
    .children
      .file e2e
      .children
        .file scenarios.js
      .file unit
      .children
        .file checkmark.filter.spec.js
        .file phone_detail.controller.spec.js
        .file phone.factory.spec.js
        .file phone_list.controller.spec.js
      .file karma.conf.js
      .file protractor-conf.js

:marked
  This is actually a pretty good starting point. In particular, this organization
  follows the [Angular Style Guide](https://github.com/johnpapa/angular-styleguide),
  which is an important [preparation step](#following-the-angular-style-guide) before
  a successful upgrade. 
  
  * Each controller, factory, and filter is in its own source file, as per the
    [Rule of 1](https://github.com/johnpapa/angular-styleguide#single-responsibility).
  * The `core`, `phoneDetail`, and `phoneList` modules are each in their
    own subdirectory. Those subdirectories contain the JavaScript code as well as
    the HTML templates that go with each particular feature. This is in line with the
    [Folders-by-Feature Structure](https://github.com/johnpapa/angular-styleguide#style-y152)
    and [Modularity](https://github.com/johnpapa/angular-styleguide#modularity)
    rules.

:marked
  ## Switching to TypeScript And Module Loading
  
  Since we're going to be writing our Angular 2 code in TypeScript, it makes sense to
  bring in the TypeScript compiler even before we begin upgrading.
  
  In order to use TypeScript's ES2015 module system to `import` and `export` code, we're
  going to need a JavaScript module loader. Our application doesn't currently
  use one, and is just using plain old `<script>` tags and the global `window` scope
  instead. We'll replace this approach with the
  [SystemJS loader](https://github.com/systemjs/systemjs).

.alert.is-helpful
  :marked
    Angular 2 itself doesn't require either TypeScript or SystemJS.
    There will soon be other editions of this guide that show how to
    do the upgrade using ES5.
    
:marked
  We will also start to gradually phase out the Bower package manager in favor
  of NPM. We'll install all new dependencies using NPM, and will eventually be
  able to remove Bower from the project.

  Let's begin by installing the SystemJS and TypeScript packages to the project.
  While we're at it, let's also install the
  [Typings type definition manager](https://github.com/typings/typings).
  It will allow us to install type definitions for libraries that don't come with
  prepackaged types.

code-example(format="").
  npm i systemjs --save
  npm i typescript typings --save-dev

:marked
  Let's also add run scripts for the `tsc` TypeScript compiler and the `typings`
  tool to `package.json`:

+makeJson('upgrade-phonecat/ts/typescript-conversion/package.1.json', {paths: 'scripts'}, 'package.json', {otl: /(\"tsc.*|\"typings.*)/g})


:marked
  We can now use Typings to install the type definitions for Angular 1 and the Jasmine
  unit test framework. This will add a `typings` directory to the project and install
  a number of `.d.ts` files under it. It will also create a `typings.json` file to the
  project, which contains metadata about the type definitions we've installed:
  
code-example(format="").
  npm run typings install jquery -- --save --ambient
  npm run typings install angular -- --save --ambient
  npm run typings install angular-route -- --save --ambient
  npm run typings install angular-resource -- --save --ambient
  npm run typings install angular-mocks -- --save --ambient
  npm run typings install jasmine -- --save --ambient

:marked
  In `index.html`, let's now enable SystemJS. Add a couple of `<script>` tags that
  load the SystemJS library and then one that loads a configuration file for
  it. Then add one more `<script>` tag that uses SystemJS to load our application.
  These will *replace* the various `<script>` tags we had earlier for loading the
  application components:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/app/index.html', 'scripts', 'app/index.html')

+makeExample('upgrade-phonecat/ts/typescript-conversion/app/systemjs.config.js', ull, 'app/systemjs.config.js')

:marked
  This tells SystemJS that we have a module called `app.module` that
  resides in the `js` subdirectory (relative to the `index.html` page). We then load that
  module using `System.import`. This will load and execute the `app/app.module.js` file.

  We should also configure the TypeScript compiler so that it can understand our
  project. We'll add a `tsconfig.json` file to the project directory, just like we did
  in the [Quickstart](../quickstart.html). It instructs the TypeScript compiler how
  to interpret our source files.
  
+makeJson('upgrade-phonecat/ts/typescript-conversion/tsconfig.1.json', null, 'tsconfig.json')

:marked
  We are telling the TypeScript compiler to turn our TypeScript files to ES5 code
  bundled into SystemJS modules. In other words, our compiler target is something
  SystemJS can load and all major browsers are able to run.
  
  We can now launch the TypeScript compiler from the command line. It will watch
  our `.ts` source files and compile them to JavaScript on the fly. Those compiled
  `.js` files are then loaded into the browser by SystemJS. This is a process we'll
  want to have continuously running in the background as we go along.

code-example(format="").
  npm run tsc

:marked
  The next thing we'll do is convert our JavaScript files to TypeScript and define
  their imports and exports. Each file should now explicitly export the things
  it wants to expose, and import the things it needs from other files. This is a
  departure from the previous approach which just relied on things being available
  on the global `window` scope.

  Since TypeScript is a superset of ECMAScript 2015, which in turn is a superset
  of ECMAScript 5, we can simply switch the file extensions from `.js` to `.ts`
  and define the imports and exports. We don't need to make other changes to
  our existing code. Instead we'll introduce type annotations and other new
  features gradually over time.
  
  Let's begin by renaming `app.module.js` to `app.module.ts`. The TypeScript
  compiler should be able to compile it successfully right away. This means we can
  move right along and go through the rest of our source files and convert them.
  We'll rename each one to a `.ts` file, and add the imports and exports it needs.
  
  Beginning from the checkmark filter, here are the converted contents:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/core/checkmark.filter.ts', null, 'app/js/core/checkmark.filter.ts')

:marked
  This file now has the filter factory function as the default export. Apart from 
  the export, there's one other major change we've applied to the file, which
  is that it does *not* contain the registration of the filter into an Angular
  module. We will do that later in the `core` module's main file. 
  
  Moving to the `Phone` factory file, it now has the factory function as the default
  export:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/core/phone.factory.ts', null, 'app/js/core/phone.factory.ts')

:marked
  The `core` module's main module file will now import both the checkmark filter
  and the Phone factory. This is where we actually register them into the Angular module.
  We then export the module itself as this file's default export:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/core/core.module.ts', null, 'app/js/core/core.module.ts')

:marked
  Notice that with this organization pattern, the files that hold the application
  components themselves - filters and factories - aren't concerned with the makeup
  of Angular modules. That's just something we previously *had* to do because there
  were no other good solutions. Now we use a separate file just for the purpose
  of forming the Angular module.
  
  Now switching to the phone detail module, we'll make similar changes here. In the
  controller file we export the controller function as the default export:

+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/phone_detail/phone_detail.controller.ts', null, 'app/js/phone_detail/phone_detail.controller.ts')

:marked
  In the main module file we import the controller and register it into the Angular
  module, which itself is then exported:

+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/phone_detail/phone_detail.module.ts', null, 'app/js/phone_detail/phone_detail.module.ts')

:marked
  Then we'll repeat the same steps once more for the phone list module.
  The controller file exports the controller function:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/phone_list/phone_list.controller.ts', null, 'app/js/phone_list/phone_list.controller.ts')

:marked
  And the main module file imports the controller and registers it:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/phone_list/phone_list.module.ts', null, 'app/js/phone_list/phone_list.module.ts')

:marked
  Finally, we can now pull everything together in `app.module.ts`. We'll
  import each of the three submodule files and register them as dependencies
  of the main application module:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/app.module.ts', 'pre-bootstrap', 'app/js/app.module.ts')

:marked
  Note that we don't have to repeat the submodule name strings here. Since the
  modules export themselves, we can just refer to the `name` attribute of each 
  of them.
  
  Before this converted version of the application will run, we need to change the
  way we're bootstrapping it. It is currently bootstrapped using the `ng-app` directive
  attached to the `<html>` element of the host page. This will no longer work because
  `ng-app` is processed when the page loads, and our application code will not
  be available at that point yet. It is loaded asynchronously by SystemJS instead.
  
  We should switch to a JavaScript-driven bootstrap instead. As it happens, this is
  also how Angular 2 apps are bootstrapped, so the switch brings us one step closer
  to Angular as well. So, remove the `ng-app` attribute from `index.html`, and add
  this at the end of `app.module.ts`:

+makeExample('upgrade-phonecat/ts/typescript-conversion/app/js/app.module.ts', 'bootstrap', 'app/js/app.module.ts')

:marked
  We now have a fully functional version of the application, all converted
  into TypeScript code and a modern module system! If you start the project HTTP
  server with `npm start`, you should see the fully functional application in
  your browser. On the other hand, if you were to try running the *test suite*,
  things wouldn't look quite that good yet. We also have to make our tests
  support our new module organization.
  
:marked
  ## Preparing Tests
  
  Our project has both E2E Protractor tests and some Karma unit tests in it.
  Of these two, E2E tests can be dealt with much quicker: By definition,
  E2E tests access our application from the *outside* by interacting with 
  the various UI elements the app puts on the screen. E2E tests aren't really that
  concerned with the internal structure of the application components. That
  also means that although we've modified our project quite a bit, the E2E
  test suite should keep passing just as it was before. We haven't changed
  how the app behaves from the user's point of view.
  
  For unit tests, on the other hand, we'll do a bit of conversion work.
  What we'll do is convert our existing unit tests to TypeScript and have them
  use `import`s to load in the code they need.
  
  We'll also need to tweak our Karma configuration so that it'll let SystemJS load
  the application files. For this we'll use a shim file that will tweak the way
  files get loaded:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/test/karma_test_shim.js', null, 'test/karma_test_shim.js')

.alert.is-important The shim is likely to be replaced by improved tooling, but is currently needed.

:marked
  We'll then update the Karma configuration file, so that it loads SystemJS and the
  shim file. We'll also change how the app and unit tests files themselves are loaded.
  We will *watch* them so that the test suite is triggered when changes occur, but we
  won't have Karma *include* them because that is now done by SystemJS and the shim.
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/test/karma.conf.1.js', 'files', 'test/karma.conf.js')

:marked
  Now we have the infrastructure in place and can convert the test files themselves.
  This mainly just consists for changing the file extensions of those files, and adding
  the necessary imports to them.
  
  In the checkmark filter spec, we'll import the core module file, so that it is
  available when we load the corresponding Angular module:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/test/unit/checkmark.filter.spec.ts', 'top', 'test/unit/checkmark.filter.spec.ts')

:marked
  We'll do the exact same thing for the phone factory spec:

+makeExample('upgrade-phonecat/ts/typescript-conversion/test/unit/phone.factory.spec.ts', 'top', 'test/unit/phone.factory.spec.ts')

:marked
  In the phone detail controller spec, on the other hand, we should import
  the phone detail module:

+makeExample('upgrade-phonecat/ts/typescript-conversion/test/unit/phone_detail.controller.spec.ts', 'top', 'test/unit/phone_detail.controller.spec.ts')

:marked
  Finally, the phone list controller spec should import the phone list
  module:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/test/unit/phone_list.controller.spec.ts', 'top', 'test/unit/phone_list.controller.spec.ts')

:marked
  There's one more issue we have in our controller tests, which is that TypeScript
  isn't happy about compiling them at the moment. This is because we're using
  the custom Jasmine matcher `toEqualData` in both of them. Because this is something
  we define ourselves, it isn't included in the Jasmine type definitions that we
  installed using Typings.
  
  We can add our own little type definition file for that extension, which extends
  the `jasmine.Matchers` interface and adds our custom matcher to it. This will
  satisfy the compiler and let us use our custom matcher while retaining the nice
  type safety features of TypeScript:
  
+makeExample('upgrade-phonecat/ts/typescript-conversion/test/jasmine_matchers.d.ts', null, 'test/jasmine_matchers.d.ts')

:marked
  And now we have a fully functional test suite for our TypeScript-enabled
  application as well.
  
:marked
  ## Enjoying The Benefits of TypeScript
  
  Now that we have TypeScript, we can start benefiting from some of its
  other features in addition to the imports and exports that we're already using.
  There's a lot of value the language can provide in Angular 1 applications.
  
  For one thing, TypeScript is a superset of ES2015. Any app that has previously
  been written in ES5 - like the PhoneCat example has - can with TypeScript
  start incorporating all of the JavaScript features that are new to ES2015.
  These include things like `let`s and `const`s, default function parameters,
  and destructuring assignments.
  
  Another thing we can do is start adding *type safety* to our code, by
  adding type annotations. For instance, we can annotate the checkmark
  filter so that it expects booleans as arguments and returns strings.
  This makes it clearer what the filter is supposed to do, and makes it
  possible for the TypeScript compiler to notify us when we're trying to
  use it with incompatible types.
  
+makeExample('upgrade-phonecat/ts/classes/app/js/core/checkmark.filter.ts', null, 'app/js/core/checkmark.filter.ts', {otl: /(:\w+)/g})
  
.l-sub-section
  :marked
    The [Angular 1.x type definitions](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/angularjs)
    we installed with Typings are not officially maintained by the Angular team,
    but are quite comprehensive. Though we're not going to do it in this
    tutorial, it is possible to make an Angular 1.x application fully
    type-annotated with the help of these definitions.
    
    If this is something we wanted to do, it would be a good idea to enable 
    the `noImplicitAny` configuration option in `tsconfig.json`. This would
    cause the TypeScript compiler to display a warning when there's any code that
    does not yet have type annotations. We could use it as a guide to inform
    us about how close we are to having a fully annotated project.
  
:marked
  Another TypeScript feature we can make use of is *classes*. In particular, we
  can turn our controllers into classes. That way they'll be a step
  closer to becoming Angular 2 component classes, which will make our life
  easier once we do the upgrade.
  
  Angular 1 expects controllers to be constructor functions. That's what
  ES2015/TypeScript classes really are, so that means we can just register a
  class as a controller and Angular 1 will happily use it. We also won't 
  need to make any changes to our test suite as the external behavior of the
  controllers will not change.
  
  Here's what our new class for the phone list controller looks like.
  
+makeExample('upgrade-phonecat/ts/classes/app/js/phone_list/phone_list.controller.ts', null, 'app/js/phone_list/phone_list.controller.ts')

:marked
  What was previously done in the controller function is now done in the class
  constructor function. The class additionally declares three members: The 
  array of phones, the name of the current sort key, and the search query. These
  are all things we have already been attaching to the controller,
  but that weren't explicitly declared anywhere. The last one of these isn't actually
  used in the TypeScript code since it's only referred to in the template, but for
  the sake of clarity we want to define all the members our controller will have.

  In the Phone detail controller we'll have two members: One for the phone
  that the user is looking at and another for the URL of the currently displayed image.
  We can additionally introduce a TypeScript interface that explicitly defines
  what we expect the `$routeParams` object to contain when it is
  passed to the controller. This interface is not exported and is just used internally
  inside this module:
  
+makeExample('upgrade-phonecat/ts/classes/app/js/phone_detail/phone_detail.controller.ts', null, 'app/js/phone_detail/phone_detail.controller.ts')
  
:marked
  This makes our controller code look a lot more like Angular 2 already. We're
  all set to actually introduce Angular 2 into the project.
  
  If we had any Angular 1 services in the project, those would also be
  a good candidate for converting to classes, since like controllers,
  they're also constructor functions. But we only have the `Phone` factory
  in this project, and that's a bit special since it's an `ngResource`
  factory. So we won't be doing anything to it in the preparation stage.
  We'll instead turn it directly into an Angular 2 service in the
  next section.







.l-main-section
:marked
  # PhoneCat Upgrade Tutorial
  
  Having completed our preparation work, let's get going with the Angular 2
  upgrade of PhoneCat. We'll do this incrementally with the help of the
  [upgrade module](#upgrading-with-the-upgrade-adapter) that comes with Angular 2.
  By the time we're done, we'll be able to remove Angular 1 from the project
  completely, but the key is to do this piece by piece without breaking the application.
  
.alert.is-important The project also contains some animations, which we are not yet upgrading in this version of the guide. This will change in a later release.
  
:marked
  Let's install Angular 2 into the project. Add the Angular 2 dependencies
  to `package.json` and `typings.json` as described in the [Quickstart](../quickstart.html).
  Then run:

code-example(format="").
  npm install
  npm run typings install
  
:marked
  We should then load some Angular 2 dependencies into the application by adding
  some `<script>` tags to `index.html`. They should go before the `<script>` tag
  that loads `systemjs.config.js`:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/index.html', 'ng2')

:marked
  We can then load Angular 2 itself by adding its packages into the `systemjs.config.js`
  file:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/systemjs.config.js', null, 'app/systemjs.config.js')

:marked
  While we're at it, let's also make these files available to unit tests by
  updating the Karma config:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/test/karma.conf.1.js', 'ng2', 'test/karma.conf.js')

:marked
  ## Bootstrapping A Hybrid 1+2 PhoneCat

  What we'll do next is bootstrap the application as a *hybrid application*
  that supports both Angular 1 and Angular 2 components. Once we've done that
  we can start converting the individual pieces to Angular 2.
  
  At this point we need to do add the Angular 2 type definitions
  into `app.ts`, so that the TypeScript compiler knows what we're talking about
  when we use Angular 2 APIs. Unlike with Angular 1, we don't need to install
  these type definitions with Typings because Angular 2 comes with them included.
  What we do need to do is set the TypeScript compiler's `moduleResolution` option
  to `node`, so that it knows to look for these definitions from the `angular2` NPM
  package.
  
+makeJson('upgrade-phonecat/ts/ng2_initial/tsconfig.1.json', null, 'tsconfig.json', {otl: /(\"moduleResolution.*)/})

:marked
  To boostrap a hybrid application, we first need to initialize an `UpgradeAdapter`,
  which [provides the glue](#upgrading-with-the-upgrade-adapter) that joins the two
  versions of the framework together. Let's import the `UpgradeAdapter` class into
  `app.module.ts`:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/app.module.ts', 'adapter-import', 'app/js/app.module.ts')

:marked
  We can then make an adapter by instantiating the class:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/core/upgrade_adapter.ts', 'adapter-init')
  
:marked
  Now we can use that adapter to bootstrap our application as a hybrid.
  Instead of calling `angular.bootstrap`, we must call
  `upgradeAdapter.bootstrap`, but the function arguments remain the same:
  They are still the element that will become the root of the application,
  and the names of the root Angular 1.x modules that we want to include:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/app.module.ts', 'bootstrap')
  
:marked
  We are now running both Angular 1 and 2 at the same time. That's pretty
  exciting! We're not running any actual Angular 2 components yet though,
  so let's do that next.
  
    
:marked
  ## Upgrading the Phone factory

  The first piece we'll port over to Angular 2 is the `Phone` factory, which
  resides in `app/js/core/phones.factory.ts` and makes it possible for controllers
  to load phone information from the server. Right now it's implemented with
  ngResource and we're using it for two things:
  
  * For loading the list of all phones into the phone list controller
  * For loading the details of a single phone into the phone detail controller.
  
  We can replace this implementation with an Angular 2 service class, while 
  keeping our controllers in Angular 1 land. In the new version we'll just use
  the `Http` service from Angular 2 instead of ngResource.
  
  Before the `Http` service is available for injection, we need to register
  it into our application's dependency injector. We should import the `HTTP_PROVIDERS`
  constant in `app.module.ts`:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/app.module.ts', 'http-import')

:marked
  In a regular Angular 2 application we would now pass `HTTP_PROVIDERS` into
  the application bootstrap function. But we can't do that in a hybrid
  application such as the one we're working on. That's because the `bootstrap`
  method of  `UpgradeAdapter` expects Angular 1 modules as dependencies,
  not Angular 2 providers.
  
  What we must do instead is register `HTTP_PROVIDERS` into the `UpgradeAdapter`
  separately. It has a method called `addProvider` for that purpose:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/app.module.ts', 'add-http-providers')

:marked
  Now we're ready to upgrade the Phones factory itself. We'll put the Angular 2
  implementation in a new file called `phones.service.ts` in the core module. It will be a TypeScript
  class decorated as `@Injectable`:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/core/phones.service.ts', 'class', 'app/js/core/phones.service.ts')

:marked
  The `@Injectable` decorator will attach some dependency injection metadata
  to the class, letting Angular 2 know about its dependencies. As described
  by our [Dependency Injection Guide](../guide/dependency-injection.html),
  this is a marker decorator we need to use for classes that have no other
  Angular 2 decorators but still need to have their dependencies injected. 
  
  In its constructor the class expects to get the `Http` service. It will
  be injected to it and it is stored as a private field. The service is then
  used in the two instance methods, one of which loads the list of all phones,
  and the other the details of a particular phone:

+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/core/phones.service.ts', 'fullclass')

:marked
  The methods now return Observables of type `Phone` and `Phone[]`. This is
  a type we don't have yet, so let's add a simple interface for it:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/core/phones.service.ts', 'phone-interface', 'app/js/core/phones.service.ts')

:marked
  Here's the full, final code for the service:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/core/phones.service.ts', 'full', 'app/js/core/phones.service.ts')

:marked
  Notice that we're importing the `map` operator of the RxJS `Observable` separately.
  We need to do this for all RxJS operators that we want to use, since Angular 2
  does not load all of them by default.

  The new `Phones` service now has the same features that the original, ngResource based
  service did. You can remove the old `phones.factory.ts` file. Now we just
  need to register the new service into the application, so that our Angular 1
  controllers will be able to use it.
  
  `UpgradeAdapter` has a `downgradeNg2Provider` method for the purpose of making
  Angular 2 services available to Angular 1 code. The problem is that we don't have
  our `UpgradeAdapter` available in `core.module.ts` where the `Phones` service should
  be registered. We only have it in `app.module.ts`. There should only be one
  `UpgradeAdapter` in an application, so we need to find a way to share our
  instance between the two code modules.
  
  What we'll do is create a new module that instantiates `UpgradeAdapter`
  and exports the instance. We can then just pull it in wherever we need it,
  so that we're using the same object everywhere. Let's put this new file
  under `core`:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/core/upgrade_adapter.ts', 'full', 'app/js/core/upgrade_adapter.ts')

:marked
  In `app.module.ts` we should now just import this adapter instead of making a separate one:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/app.module.ts', 'adapter-state-import')

:marked
  Also remove the line from `app.module.ts` that is instantiating `UpgradeAdapter`. It's no
  longer needed since we import the instance from elsewhere.
  
  We'll then do the same in `core.module.ts` as well. Then we can register the `Phones` service into it.
  While doing that, we can remove the module's dependency to `ngResource`, which
  we're no longer using.
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/core/core.module.ts', null, 'app/js/core/core.module.ts')

:marked
  Note that we actually needed to do two registrations here:
  
  1. Register `Phones` as an **Angular 2 provider** with the `addProvider`
     method. That's the same method that we used earlier for `HTTP_PROVIDERS`.
  2. Register an **Angular 1 factory** called `phones`, which will be a *downgraded*
     version of the `Phones` service.
     
  At this point we can switch our two controllers to use the new service
  instead of the old one. We `$inject` it as the downgraded `phones` factory,
  but it's really an instance of the `Phones` class and we can annotate its type
  accordingly:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/phone_detail/phone_detail.controller.ts', null, 'app/js/phone_detail/phone_detail.controller.ts')

+makeExample('upgrade-phonecat/ts/ng2_initial/app/js/phone_list/phone_list.controller.ts', null, 'app/js/phone_list/phone_list.controller.ts')

:marked
  What we have here are two Angular 1 controllers using an Angular 2 service!
  The controllers don't need to be aware of this, though the fact that the
  service returns Observables and not Promises is a bit of a giveaway.
  In any case, what we've achieved is a migration of a service to Angular 2
  without having to yet migrate the controllers that use it.
  
.alert.is-helpful
  :marked
    You could use the `toPromise` method of `Observable` to turn those Observables
    into Promises in the service to further reduce the amount of changes
    needed in controller code.
  
:marked
  To bring our test suite up to speed with the changes, we should update the Karma
  test shim. It'll make some of Angular 2 providers available before starting
  to load any of the spec files:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/test/karma_test_shim.js', null, 'test/karma_test_shim.js')

.alert.is-important The shim is likely to be replaced by improved tooling, but is needed right now.

:marked
  Now, let's look at the tests for the service itself. What we used to have in 
  `phones_factory_spec.js` was a fairly simple test that simply checks if
  the factory exists and is available for injection. We can now do that same
  test in Angular 2. Rename `phones.factory.spec.ts` to `phones.service.spec.ts` and
  set the contents as follows:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/test/unit/phones.service.spec.ts', null, 'test/unit/phones.service.spec.ts')

:marked
  Here we first load the `Phones` provider and then test that an instance of
  `Phones` can in fact be injected. We also need to load `HTTP_PROVIDERS` since
  it is a dependency of `Phones`.
  
  For the controller tests, we can first of all at this point get rid of the
  custom `toEqualData` custom matcher. It was added because `ngResource` attaches
  attributes to the data that we don't want to compare in tests. We're no longer
  using `ngResource`, so we can simply use the built-in `toEqual` for comparisons.
  This means we can remove the `test/jasmine_matchers.d.ts` file at this point.
  
  Now, in the phone detail controller we have been testing that the phone details
  with the id given in the route params are fetched over HTTP and put on the
  scope. We can continue doing that, but we'll need to change the structure of the
  test a bit. Instead of using the Angular 1 mock HTTP backend, we'll just mock out
  the `get` method of the `Phones` service, which is what the controller is now
  using to load what it needs. As the mocked value, we're returning an Observable
  that will emit a single value - the mock phone data:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/test/unit/phone_detail.controller.spec.ts', null, 'test/unit/phone_detail.controller.spec.ts')

.alert.is-important
  :marked
    We're doing a manual `Phones` instantiation because hybrid apps can't be
    bootstrapped for unit tests at the moment, which means that Angular 2
    dependencies can't be made available. This is likely to change.

:marked
  In the phone list controller we'll do something very similar: We mock out the `query`
  method of the `Phones` service, and check that the controller makes the resulting
  value available:
  
+makeExample('upgrade-phonecat/ts/ng2_initial/test/unit/phone_list.controller.spec.ts', null, 'test/unit/phone_list.controller.spec.ts')

:marked
  ## Upgrading Controllers to Components
  
  Next, let's upgrade our Angular 1 controllers to Angular 2 components. We'll
  do it one at a time, while still keeping the application in hybrid mode.
  As we make these conversions, we'll also be defining our first Angular 2 *pipes*.
  
  Let's look at the phone list controller first. Right now it is a TypeScript class,
  which is paired with an HTML template by the route configuration in `app.ts`.
  We'll be turning it into an Angular 2 component.
  
  Rename `phone_list.controller.ts` to `phone_list.component.ts`. Then rename the controller class
  inside to just `PhoneList` and decorate it as a `@Component`:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_list_without_pipes.component.ts', 'top', 'app/js/phone_list/phone_list.component.ts')

:marked
  The `selector` attribute is a CSS selector that defines where on the page the component
  should go. It will match elements by the name of `pc-phone-list`. It is a good idea
  to always use application-specific prefixes in selectors so that they never clash with
  built-in ones, and here we're using `pc-`, which is short for "PhoneCat".
  
  The `templateUrl` defines the location of the component template. It points to our existing
  template file
  
  Both of these attributes are things that were defined *externally* for the controller,
  but for the component are things that it defines *itself*. This will affect how we use
  the component in the router.
  
:marked
  We now also need to convert the template of this component into Angular 2 syntax.
  In the search controls we need to use Angular 2 syntax for the two `ngModel`s
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_list_without_pipes.html', 'controls', 'app/js/phone_list/phone_list.html')

:marked
  In the list we need to replace the `ng-repeat` with an `*ngFor` and its
  `#var of iterable` syntax, which is [described in our
  Template Syntax guide](../guide/template-syntax.html#directives).
  
  For the images, we can replace `ng-src` with the standard `src`, but will use a
  property binding. Note that we're also adding a `name` CSS class for the phone name.
  This is something we'll need for our Protractor tests:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_list_without_pipes.html', 'list', 'app/js/phone_list/phone_list.html')

:marked
  In the module file we're going to plug this component into our application. Instead
  of registering a controller, we register a `pcPhoneList` directive.
  The directive is a downgraded version of our component, and the `UpgradeAdapter`
  handles the bridging between the two:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_list.module.ts', null, 'app/js/phone_list/phone_list.module.ts')

:marked
  The `<angular.IDirectiveFactory>` type annotation here is to let the TypeScript compiler
  know that the return value of the downgrade method call will be something that can be
  used as a directive factory.
  
  To complete the switch, we should change our route configuration in `app.module.ts`.
  Instead of using the controller and template, it can just instantiate our component.
  We can do that by using a simple template that uses the directive
  we just registered:

+makeExample('upgrade-phonecat/ts/ng2_components/app/js/app.module.ts', 'list-route')

:marked
  When the application runs, the Angular 1.x directive compiler will match
  the element in the template to the `pcPhoneList` directive, which is actually
  an Angular 2 component!
  
  The remaining issue with the phone list is the use of filters in its
  template: It is referring to the `filter` filter and the `orderBy` filter,
  and relying on them to filter and sort the phone list, respectively.
  These pipes do not exist in Angular 2, so we're going to need to do
  the filtering and sorting ourselves. Let's define a couple of pipes that
  get the job done.

.alert.is-helpful
  :marked
    If you want to learn more about how pipes in Angular 2
    work, we have [a whole guide on the subject](../guide/pipes.html)
    available!
    
:marked
  For filtering, we'll have a pipe called `PhoneFilterPipe`. It works like 
  the `filter` filter in Angular 1 in that it filters a collection of objects,
  matching properties within the objects. But, as opposed to `filter`,
  this pipe is specialized to filter `Phone` objects and we can use
  type annotations to make this explicit:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_filter.pipe.ts', null, 'app/js/phone_list/phone_filter.pipe.ts')

:marked
  Since we're adding new code, it's a good idea to add some unit tests for
  it too. Here are a few tests for `PhoneFilterPipe`:
  
+makeExample('upgrade-phonecat/ts/ng2_components/test/unit/phone_filter.pipe.spec.ts', null, 'test/unit/phone_filter.pipe.spec.ts')

:marked
  For sorting, we'll use a more generic pipe, just called `OrderBy`. It
  takes an array of objects, and a property to order the array by. It returns
  an array of the same type of thing it was given. In the implementation we
  copy the input array, sort the copy, and return it.
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/order_by.pipe.ts', null, 'app/js/phone_list/order_by.pipe.ts')

:marked
  Here's a unit test for `OrderByPipe` as well:
  
+makeExample('upgrade-phonecat/ts/ng2_components/test/unit/order_by.pipe.spec.ts', null, 'test/unit/order_by.pipe.spec.ts')

:marked
  We can now integrate these new pipes with our component. Before the pipes
  are available there, we need to declare them in the `@Component` decorator.
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_list.component.ts', 'top', 'app/js/phone_list/phone_list.component.ts')

:marked
  In the template we need to use the `phoneFilter` pipe instead of `filter`.
  No changes are needed for the `orderBy`
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_list_without_async.html', 'list', 'app/js/phone_list/phone_list.html')

:marked
  Now that the phone list is an Angular 2 component, there's one more neat trick
  we can apply to make its code a little bit simpler. Earlier, as we upgraded
  the `Phones` service, we needed to add a `subscribe` callback to the list
  response, which populated the `phones` array on the component.
  With Angular 2, we can instead just put the Observable itself on the
  component, and can skip the subscription callback:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_list.component.ts', 'full', 'app/js/phone_list/phone_list.component.ts')

:marked
  This is made possible by the `async` pipe, which we can apply in the template.
  It knows how to turn an Observable to the (latest) value it has emitted:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_list/phone_list.html', 'list', 'app/js/phone_list/phone_list.html')

:marked
  That takes care of the phone list. Here's the updated unit test file for
  that component to complete the migration:
  
+makeExample('upgrade-phonecat/ts/ng2_components/test/unit/phone_list.component.spec.ts', null, 'test/unit/phone_list.component.spec.ts')

:marked
  Before this test will run, we'll need to augment our Karma configuration
  so that component HTML templates are loaded properly. We didn't need them
  before when we were testing the controller in isolation, but our new test
  exercises the component as a whole, which includes the template.
  
+makeExample('upgrade-phonecat/ts/ng2_components/test/karma.conf.1.js', 'html', 'test/karma.conf.js')

:marked
  Now we can start looking at our other controller, which is the one for
  the phone details. Rename `phone_detail.controller.ts` to `phone_detail.component.ts`,
  and set the contents as follows:
    
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_detail/phone_detail_without_pipes.component.ts', null, 'app/js/phone_detail/phone_detail.component.ts')

:marked
  This is pretty similar to what we did with the phone list. The one new change
  here is the use of `@Inject` for the `$routeParams` dependency. It tells the
  Angular 2 injector what this dependency should map to. We have a dependency called
  `$routeParams` in the Angular 1 injector, where it is provided by the Angular 1 router.
  That is what we were already using when `PhoneDetails` was still an Angular 1 controller.
  The things is though, Angular 1 dependencies are not made automatically available to
  Angular 2 components, so if we were to run this now, it would not work.
  
  We explicitly need to tell the `UpgradeAdapter` to upgrade `$routeParams` so that
  it is available for injection in Angular 2. We can do it in `app.module.ts`:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/app.module.ts', 'upgrade-route-params', 'app/js/app.module.ts')

  
    
:marked
  We now also need to convert the template of this component into Angular 2 syntax.
  Here is the new template in its entirety:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_detail/phone_detail.html', null, 'app/js/phone_detail/phone_detail.html')

:marked
  There are several notable changes here:
  
  * We've removed the `vm.` prefix from all expressions.
  * Just like we did in the phone list, we've replaced `ng-src` with property
    bindings for the standard `src`.
  * We're using the property binding syntax around `ng-class`. Though Angular 2
    does have [a very similar `ngClass`](../guide/template-syntax.html#directives)
    as Angular 1 does, its value is not magically evaluated as an expression.
    In Angular 2 we always specify  in the template when an attribute's value is
    a property expression, as opposed to a literal string.
  * We've replaced `ng-repeat`s with `*ngFor`s.
  * We've replaced `ng-click` with an event binding for the standard `click`.
  * In all references to `phone`, we're using the safe navigation operator `?.` for
    safe property navigation. We need it because when the component first loads,
    we don't have `phone` yet and the expressions will refer to a non-existing
    value. Unlike in Angular 1, Angular 2 expressions do not fail silently when
    we try to refer to properties on undefined objects. We need to be explicit
    about cases where this is expected.
    
:marked
  In the module file we'll now register a `pcPhoneDetail` directive instead of a
  controller. The directive is a downgraded version of the `PhoneDetail` component.
    
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_detail/phone_detail.module.ts', null, 'app/js/phone_detail/phone_detail.module.ts')

:marked
  In the router configuration in `app.module.ts`, we'll switch the details route to
  instantiate a component as well:

+makeExample('upgrade-phonecat/ts/ng2_components/app/js/app.module.ts', 'detail-route')

:marked
  There's one additional step we need to take, which is to upgrade the
  `checkmark` filter that the template is using. We need an Angular 2
  pipe instead of an Angular 1 filter.
  
  While there is no upgrade method in the upgrade adapter for filters, we
  can just turn the filter function into a class that fulfills
  the contract for Angular 2 Pipes. The implementation is the same as before.
  It just comes in a different kind of package. While changing it, also
  rename the file to `checkmark.pipe.ts`:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/core/checkmark.pipe.ts', null, 'app/js/core/checkmark.pipe.ts')

:marked
  As we apply this change, we should also remove the registration of the filter
  from the core module file. The module's content becomes:

+makeExample('upgrade-phonecat/ts/ng2_components/app/js/core/core.module.ts', null, 'app/js/core/core.module.ts')

:marked
  The unit test file for the filter also now becomes the unit test filter
  for the pipe. While we're still testing the same thing, we need to change
  how we set things up:
  
+makeExample('upgrade-phonecat/ts/ng2_components/test/unit/checkmark.pipe.spec.ts', null, 'test/unit/checkmark.pipe.spec.ts')

:marked
  In the component we should now import and declare our newly created pipe:
  
+makeExample('upgrade-phonecat/ts/ng2_components/app/js/phone_detail/phone_detail.component.ts', 'top', 'app/js/phone_detail/phone_detail.component.ts')

:marked
  With the phone detail component now migrated as well, we can go and migrate
  its unit tests too.
  
+makeExample('upgrade-phonecat/ts/ng2_components/test/unit/phone_detail.component.spec.ts', null, 'test/unit/phone_detail.component.spec.ts')

:marked
  As we discussed earlier, Protractor tests should largely remain functional
  as we are making changes, since we're not really changing the user-visible
  behavior of the application. Now that we've migrated some components and
  their templates, however, there are a few changes we need to make. Apply
  the following replacements to `scenarios.js`:
  
table
  tr
    th Previous code
    th New code
    th Notes
  tr
    td
      :marked
        `by.repeater('phone in vm.phones').column('phone.name')`
    td
      :marked
        `by.css('.phones .name')`
    td
      :marked
        The repeater matcher relies on Angular 1 `ng-repeat`
  tr
    td
      :marked
        `by.repeater('phone in vm.phones')`
    td
      :marked
        `by.css('.phones li')`
    td
      :marked
        The repeater matcher relies on Angular 1 `ng-repeat`
  tr
    td  
      :marked
        `by.model('vm.query')`
    td
      :marked
        `by.css('input')`
    td
      :marked
        The model matcher relies on Angular 1 `ng-model`
  tr
    td
      :marked
        `by.model('vm.orderProp')`
    td
      :marked
        `by.css('select')`
    td
      :marked
        The model matcher relies on Angular 1 `ng-model`
  tr 
    td
      :marked
        `by.binding('vm.phone.name')`
    td
      :marked
        `by.css('h1')`
    td
      :marked
        The binding matcher relies on Angular 1 data binding
  tr
    td
      :marked
        `li:nth-child(1)` and `li:nth-child(3)` 
    td
      :marked
        `li:nth-of-type(1)` and `li:nth-of-type(3)`
    td
      :marked
        Angular 2 may inject empty `<script>` tags to the page for its internal purposes so we should not rely on the number of siblings being predictable.
      
:marked
  ## Switching To The Angular 2 Router And Bootstrap

  At this point we've replaced all our Angular 1 application components with
  their Angular 2 counterparts. The application is still bootstrapped as a hybrid,
  but there isn't really any need for that anymore, and we can begin to 
  pull out the last remnants of Angular 1.
  
  There are just two more things to do: We need to switch the router to
  the Angular 2 one, and then bootstrap the app as a pure Angular 2 app.
  
  Let's do the routing part first. Angular 2 comes with a [shiny new router](router.html)
  that we can use for this.
  
  Angular 2 applications all have a *root component*, which, among other
  things, is where we should plug in the router. We don't yet have such a root
  component, because our app is still managed as an Angular 1 app.
  Let's change this now and add an `AppComponent` class into a new file
  `app.component.ts`:

+makeExample('upgrade-phonecat/ts/ng2_final/app/js/app.component.ts', null, 'app/js/app.component.ts')

:marked
  This is a component that plugs in to an `<pc-app>` element on the page,
  and has a simple template that only includes the router outlet component
  of the Angular router. This means that the component just renders the contents
  of the current route and nothing else. The `@RouteConfig` decorator defines
  the Angular 2 counterparts of our two routes. They refer directly to the
  two components.
  
  We should put this `<pc-app>` element in the HTML so that the root component
  has something to attach to. It replaces the old Angular 1 `ng-view` directive:
  
+makeExample('upgrade-phonecat/ts/ng2_final/app/index.html', 'body', 'app/index.html')

:marked
  In the `PhoneDetail` component we now need to change how the phone id parameter
  is received. There will be no more `$routeParams` injection available, because
  that comes from the Angular 1 router. Instead, what we have is a `RouteParams`
  object provided by the Angular 2 router. We use it to obtain the `phoneId` from
  the params:
  
+makeExample('upgrade-phonecat/ts/ng2_final/app/js/phone_detail/phone_detail.component.ts', null, 'app/js/phone_detail/phone_detail.component.ts')

:marked
  We should also make the corresponding change in the unit test. We provide
  an instance of the `RouteParams` class instead of the `$routeParams` object:
  
+makeExample('upgrade-phonecat/ts/ng2_final/test/unit/phone_detail.component.spec.ts', 'routeparams', 'test/unit/phone_detail.component.spec.ts')

:marked
  With that, we're ready to switch the bootstrap method of the application from that
  of the `UpgradeAdapter` to the main Angular 2 `bootstrap`. Let's import it together
  with the router and the new app component in `app.module.ts`
  
+makeExample('upgrade-phonecat/ts/ng2_final/app/js/main.ts', 'importbootstrap')

:marked
  We'll now use the regular Angular 2 `bootstrap` function to bootstrap the app 
  instead of using `UpgradeAdapter`. The first argument to `bootstrap` is the
  application's root component `AppComponent`, and the second
  is an array of the Angular 2 providers that we want to make available for
  injection. In that array we include all the things we have been registering
  with  `upgradeAdapter.addProvider` until now, as well as the providers and
  directives of the router:
  
+makeExample('upgrade-phonecat/ts/ng2_final/app/js/main.ts', 'bootstrap')

:marked
  We are now running a pure Angular 2 application!
  
  But there's actually one more cool thing we can do with the new router.
  We no longer have to hardcode the links to phone details from the phone 
  list, because the Angular 2 router is able to generate them for us with
  its `routerLink` directive. We just need to refer to the route names we
  used in the `@RouteConfig`:
  
+makeExample('upgrade-phonecat/ts/ng2_final/app/js/phone_list/phone_list.html', 'list', 'app/js/phone_list/phone_list.html')

:marked
  For this to work the directive just needs to be declared in the component:
  
+makeExample('upgrade-phonecat/ts/ng2_final/app/js/phone_list/phone_list.component.ts', 'top')

:marked
  Also, the unit tests for `PhoneList` now need to set up some router providers
  so that the `RouterLink` directive can be injected in the tests:

+makeExample('upgrade-phonecat/ts/ng2_final/test/unit/phone_list.component.spec.ts', null)

:marked
  To bring our Protractor test suite up to speed with the latest changes,
  there are a few remaining things we need to do. Firstly, now that we're
  no longer running Angular 1 at all, we should let Protractor know it
  should not be looking for one but instead find *Angular 2 apps* from
  the page. Add the following configuration option to `protractor-conf.js`:
  
+makeExample('upgrade-phonecat/ts/ng2_final/test/protractor-conf.js', 'ng2')

:marked
  Also, there are a couple of Protractor API calls in our test code that
  are using the Angular 1 `$location` service under the hood. As that
  service is no longer there, we need to replace those calls with ones
  that use WebDriver's generic URL APIs instead. The first of these is
  the redirection spec:
  
+makeExample('upgrade-phonecat/ts/ng2_final/test/e2e/scenarios.js', 'redirect')

:marked
  And the second is the phone links spec:
  
+makeExample('upgrade-phonecat/ts/ng2_final/test/e2e/scenarios.js', 'links')

:marked
  Now our E2E test suite is passing too, and we're ready to remove
  Angular 1 from the project!

:marked
  ## Saying Goodbye to Angular 1

  It is time to take off the training wheels and let our application begin
  its new life as a pure, shiny Angular 2 app. The remaining tasks all have to
  do with removing code - which of course is every programmer's favorite task!
  
  First, rename `app.module.ts` to `main.ts`. It will no longer be setting up
  an Angular 1 module, so it doesn't really make sense to call it a module.
  Then remove all references to the `UpgradeAdapter` from `main.ts`. Also remove
  the Angular 1 bootstrap code and the imports of the `core`, `phoneList`, and
  `phoneDetail` modules. Instead import the `PhoneList` and `PhoneDetail`
  components directly - they are needed in the route configuration.
  
  When you're done, this is what `main.ts` should look like:
  
+makeExample('upgrade-phonecat/ts/ng2_final/app/js/main.ts', null, 'app/js/main.ts')

:marked
  You may also completely remove the following files. They are Angular 1
  module configuration files and type definition files, and not required
  in Angular 2:
  
  * `app/js/core/core.module.ts`
  * `app/js/core/upgrade_adapter.ts`
  * `app/js/phone_detail/phone_detail.module.ts`
  * `app/js/phone_list/phone_list.module.ts`

  The external typings for Angular 1 may be uninstalled as well. The only ones
  we still need are for Jasmine.

code-example(format="").
  npm run typings uninstall jquery -- --save --ambient
  npm run typings uninstall angular -- --save --ambient
  npm run typings uninstall angular-route -- --save --ambient
  npm run typings uninstall angular-resource -- --save --ambient
  npm run typings uninstall angular-mocks -- --save --ambient

:marked
  Finally, from `index.html` and `karma.conf.js`, remove all references to
  Angular 1 scripts as well as jQuery. Instead of importing `js/app.module`
  with SystemJS, import `js/main`. When you're done, this is what `index.html`
  should look like:
  
+makeExample('upgrade-phonecat/ts/ng2_final/app/index.html', null, 'app/index.html')

:marked
  And this is what `karma.conf.js` should look like:
  
+makeExample('upgrade-phonecat/ts/ng2_final/test/karma.conf.1.js', null, 'test/karma.conf.js')

:marked
  That is the last we'll see of Angular 1! It has served us well but now
  it's time to say goodbye.