Having an existing Angular 1 application doesn't mean that we can't begin enjoying everything Angular 2 has to offer. That's beause Angular 2 comes with built-in tools for migrating Angular 1 projects over to the Angular 2 platform.
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 work. The
upgrade module in Angular 2 has
been designed to make incremental upgrading seamless.
In this chapter 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
from the original Angular 1 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 prepare and align an Angular 1 application with Angular 2
How to use the SystemJS module loader and TypeScript with Angular 1
How to develop and test a hybrid Angular 1+2 application
How to migrate an application to Angular 2 one component at a time
To follow along with the tutorial, clone the angular-phonecat repository and apply the steps as we go
Preparing for the Upgrade
In terms of project structure, this is where our work begins
This is actually a pretty good starting point. In particular, this organization follows the Angular Style Guide, which is an important preparation step before a successful upgrade.
- Each controller, factory, and filter is in its own source file, as per the Rule of 1.
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
export code, we're
use one, and is just using plain old
<script> tags and the global
instead. We'll replace this approach with the
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.
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:
npm i systemjs --save npm i typescript --save-dev
The Angular 1 framework doesn't come with built-in TypeScript type definitions. This means that if we want to have type checks for the calls we make to Angular 1 APIs, we should install its type definitions separately. For that we'll use the tsd TypeScript definition manager. Let's make sure we have it globally installed:
npm i -g tsd
We can then use tsd 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:
tsd install angular angular-route angular-resource angular-mocks jasmine
index.html, let's now enable SystemJS. Add a
<script> tag that loads
the SystemJS library and a second
<script> tag that initializes it. These
will replace the various
<script> tags we had earlier for loading the
This configuration tells SystemJS that we have a module called
resides in the
js subdirectory (relative to the
index.html page). We then load that
System.import. This will load and execute the
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. It instructs the TypeScript compiler how
to interpret our source files.
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.
Also add a
tsc run script to
package.json. We'll use it to start the TypeScript
We can now launch the TypeScript compiler from the command line. It will watch
.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.
npm run tsc
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
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
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 adding references to the Angular 1.x
.d.ts typing files to the
main application file. Rename
app.module.ts and add the following on top
of the file:
The TypeScript compiler will now know what we mean when we reference
Angular 1 APIs. It should already at this point be able to compile the
app.module.ts file successfully.
Let's then 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:
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
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:
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:
In the main module file we import the controller and register it into the Angular module, which itself is then exported:
Then we'll repeat the same steps once more for the phone list module. The controller file exports the controller function:
And the main module file imports the controller and registers it:
Finally, we can now pull everything together in
app.module.ts. It here we'll
import each of the three submodule files and register them as dependencies
of the main application module:
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
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
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.
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
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
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.
Our project has both E2E Protractor tests and some Karma unit tests in it. Both of those are going to need a bit of work.
Of these two, E2E tests are a lot easier to convert. 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.
What we can do is convert our E2E test code to TypeScript, like we've
done with the production code. To do this, you can just rename the
scenarios.js file to
scenarios.ts. After that, you'll want to declare
the global Protractor variables used in the file, so that the TypeScript
compiler knows we're accessing them on purpose:
Once we add Angular 2 to the project, we'll be able to add more type safety to this file, because Angular 2 ships with the type definitions of the Protractor framework as well.
That pretty much takes care of E2E tests for now. For unit tests we're going
to do a bit more. What we'll do is convert our existing unit tests to TypeScript
as well as have them use
imports 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
But first we should have some additional type definitions loaded, so that the TypeScript
compiler can understand the Jasmine and ngMock APIs we're using in unit tests.
Add a file called
test_helper.ts to the test directory and add a reference
to the Jasmine and mock type definitions we already installed earlier:
For Karma's SystemJS support we'll use a shim file that will tweak the way files get loaded, so that it happens through SystemJS:
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.
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:
We'll do the exact same thing for the phone factory spec:
In the phone detail controller spec, on the other hand, we should import the phone detail module:
Finally, the phone list controller spec should import the phone list module:
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
We can add our own little type definition file for that extension, which extends
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:
And now we have a fully functional test suite for our TypeScript-enabled application as well.
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
These include things like
consts, 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.
The Angular 1.x type definitions we installed from TSD 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
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.
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, and that's what ES2015/TypeScript classes really are, and 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.
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:
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
in this project, and that's a bit special since it's an
factory. So we won't be doing anything to it in the preparation stage,
but will instead turn it directly into an Angular 2 service in the
Gradually Upgrading to Angular 2
Having completed our preparation work, let's get going with the Angular 2
upgrade itself. We'll do this incrementally with the help of the
that comes with Angular 2. By the time we're done, we can remove Angular 1
from the project completely, but the key is to do it piece by piece
without breaking the application.
Let's install Angular 2 into the project. Add the Angular 2 dependencies
package.json as described in the package.json appendix of the
We can then load Angular 2 into the application by adding some
index.html. They should go before the
<script> tag with the
The first two scripts are for adding some ES6 features to older browsers that don't natively support them. The last three bring in Angular 2 itself.
While we're at it, let's also load the same files into unit tests by updating the Karma config:
After installing Angular 2, the TypeScript compiler will complain
about a clash in the global
$ variable: The jQuery typings used
by the Angular 1 typings introduce one, and the Protractor typings
used by Angular 2 introduce another. This will be resolved in a
later release. See issue #5459
for some workarounds.
Bootstrapping Hybrid 1+2 Applications
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
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
or refer to these type definitions in our source code, because Angular 2
comes with them included. What we do need to do is set the TypeScript
moduleResolution option to
node, so that it knows to look
for these definitions from the
angular2 NPM package.
Angular 2 bundles the Jasmine type definitions we need in tests, which means
that the Jasmine type definitions we installed with
tsd are now redundant.
We might as well remove them so that there's no confusion about which ones
rm -r typings/jasmine
Also remove the reference to those type definitions from
The same also goes for Protractor: Angular 2 comes with the types of the
Protractor APIs, so it's safe to remove the
declare var line from
To boostrap a hybrid application, we first need to initialize an
This is an object that comes with the
angular2/upgrade module. It provides the
glue that joins the two versions of the framework together. It can be used to
- Upgrade Angular 1 directives to Angular 2 components
- Downgrade Angular 2 components to Angular 1 directives
- Upgrade Angular 1 factories, services, and providers to Angular 2 services
- Downgrade Angular 2 services to Angular 1 factories
- Bootstrap and manage hybrid Angular 1+2 applications
Together these features allow us to very flexibly mix and match the two frameworks in our apps. This flexibility is great because there are many different kinds of Angular code out there. Even within a single app, we may need different strategies to deal with different kinds of components.
Let's import the
UpgradeAdapter class into
We can then make an adapter by instantiating the class:
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:
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.
The first piece we'll port over to Angular 2 is the
Phone factory, which
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
Http service from Angular 2 instead of ngResource.
Http service isn't included in the main Angular 2 bundle, so we need to
include it in
index.html separately. As the service uses RxJS Observables,
we also need to bring in the RxJS bundle:
We'll also do the same in
karma.conf.js so that
Http will be available in
Http service is available for injection, we still need to register
it into our application's dependency injector. We should import the
In a regular Angular 2 application we would now pass
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
UpgradeAdapter expects Angular 1 modules as dependencies,
not Angular 2 providers.
What we must do instead is register
HTTP_PROVIDERS into the
separately. It has a method called
addProvider for that purpose:
Now we're ready to upgrade the Phones factory itself. We'll put the Angular 2
implementation in a new file called
Phones.ts in the core module. It will be a TypeScript
class decorated as
Note that with Angular 2 we're switching to a new file naming scheme, and
won't be using the
feature.type.ts naming convention anymore.
@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,
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:
The methods now return Observables of type
Phone. This is
a type we don't have yet, so let's add a simple interface for it:
Here's the full, final code for the service:
Notice that we're importing the
map operator of the RxJS
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.
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
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
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
app.module.ts we should now just import this adapter instead of making a separate one:
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
we're no longer using.
Note that we actually needed to do two registrations here:
Phonesas an Angular 2 provider with the
addProvidermethod. That's the same method that we used earlier for
- Register an Angular 1 factory called
phones, which will be a downgraded version of the
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
but it's really an instance of the
Phones class and we can annotate its type
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.
To bring our test suite up to speed with the changes, we should first enable
the Angular 2 test support library in our unit test suite. We first need to
add the angular
testing bundle to list of files that Karma is loading:
Then we'll update the Karma test shim. It should load the Angular 2 browser adapter before getting to the spec files:
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
set the contents as follows:
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
it is a dependency of
For the controller tests, we can first of all at this point get rid of the
toEqualData custom matcher. It was added because
attributes to the data that we don't want to compare in tests. We're no longer
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
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:
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.
In the phone list controller we'll do something very similar: We mock out the
method of the
Phones service, and check that the controller makes the resulting
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
We'll be turning it into an Angular 2 component.
PhoneList.ts. Then rename the controller class
inside to just
PhoneList and decorate it as a
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".
templateUrl defines the location of the component template. It points to our existing
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.
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
In the list we need to replace the
ng-repeat with an
*ngFor and its
#var of iterable syntax, as described in our
Template Syntax guide.
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:
In the module file we're going to plug this component into our application. Instead
of registering a controller, we register a
The directive is a downgraded version of our component, and the
handles the bridging between the two:
<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
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:
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
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.
If you want to learn more about how pipes in Angular 2 work, we have a whole guide on the subject available!
For filtering, we'll have a pipe called
PhoneFilterPipe. It works like
filter filter in Angular 1 in that it filters a collection of objects,
matching properties within the objects. But, as opposed to
this pipe is specialized to filter
Phone objects and we can use
type annotations to make this explicit:
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
For sorting, we'll use a more generic pipe, just called
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.
Here's a unit test for
OrderByPipe as well:
We can now integrate these new pipes with our component. Before the pipes
are available there, we need to declare them in the
In the template we need to use the
phoneFilter pipe instead of
No changes are needed for the
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
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:
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:
That takes care of the phone list. Here's the updated unit test file for that component to complete the migration:
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.
Now we can start looking at our other controller, which is the one for
the phone details. Rename
PhoneDetail.ts, and set the
contents as follows:
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
We now also need to convert the template of this component into Angular 2 syntax. Here is the new template in its entirety:
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-srcwith property bindings for the standard
- We're using the property binding syntax around
ng-class. Though Angular 2 does have a very similar
ngClassas 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
- We've replaced
ng-clickwith an event binding for the standard
- In all references to
phone, we're using the elvis operator
?.for safe property navigation. We need it because when the component first loads, we don't have
phoneyet 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.
In the module file we'll now register a
pcPhoneDetail directive instead of a
controller. The directive is a downgraded version of the
In the router configuration in
app.module.ts, we'll switch the details route to
instantiate a component as well:
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 transform 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
As we apply this change, we should also remove the registration of the filter from the core module file. The module's content becomes:
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:
In the component we should now import and declare our newly created pipe:
With the phone detail component now migrated as well, we can go and migrate its unit tests too.
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
|Previous code||New code||Notes|
The repeater matcher relies on Angular 1
The repeater matcher relies on Angular 1
The model matcher relies on Angular 1
The model matcher relies on Angular 1
The binding matcher relies on Angular 1 data binding
Angular 2 may inject empty
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,
but it isn't included by default. Just like we did with
Http, we need to
include it in
index.html before the
System.config() script first:
In the main app module we need to import a few things from the router module:
Angular 2 applications all come with 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, which replaces the
configure function in
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
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
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
object provided by the Angular 2 router. We use it to obtain the
We should also make the corresponding change in the unit test. We provide
an instance of the
RouteParams class instead of the
With that, we're ready to switch the bootstrap method of the application from that
UpgradeAdapter to the main Angular 2
bootstrap. Let's import it together
with a couple of other things in
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
upgradeAdapter.addProvider until now, as well as the providers and
directives of the router:
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
routerLink directive. We just need to refer to the route names we
used in the
For this to work the directive just needs to be declared in the component:
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
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:
And the second is the phone links spec:
Now our E2E test suite is passing too, and we're ready to remove Angular 1 from the project!
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!
app.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
app.ts. Also remove
the Angular 1 bootstrap code, type definitions, and the imports of the
phoneDetail modules. Instead import the
components directly - they are needed in the route configuration.
When you're done, this is what
app.ts should look like:
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:
karma.conf.js, remove all references to
Angular 1 scripts as well as jQuery. When you're done, this is what
should look like:
And this is what
karma.conf.js should look like:
That is the last we'll see of Angular 1! It has served us well but now it's time to say goodbye.