angular/modules/@angular/core/src/application_tokens.ts
Miško Hevery d169c2434e feat(core): Add type information to injector.get() (#13785)
- Introduce `InjectionToken<T>` which is a parameterized and type-safe
  version of `OpaqueToken`.

DEPRECATION:
- `OpaqueToken` is now deprecated, use `InjectionToken<T>` instead.
- `Injector.get(token: any, notFoundValue?: any): any` is now deprecated
  use the same method which is now overloaded as
  `Injector.get<T>(token: Type<T>|InjectionToken<T>, notFoundValue?: T): T;`.

Migration
- Replace `OpaqueToken` with `InjectionToken<?>` and parameterize it.
- Migrate your code to only use `Type<?>` or `InjectionToken<?>` as
  injection tokens. Using other tokens will not be supported in the
  future.

BREAKING CHANGE:
- Because `injector.get()` is now parameterize it is possible that code
  which used to work no longer type checks. Example would be if one
  injects `Foo` but configures it as `{provide: Foo, useClass: MockFoo}`.
  The injection instance will be that of `MockFoo` but the type will be
  `Foo` instead of `any` as in the past. This means that it was possible
  to call a method on `MockFoo` in the past which now will fail type
  check. See this example:

```
class Foo {}
class MockFoo extends Foo {
  setupMock();
}

var PROVIDERS = [
  {provide: Foo, useClass: MockFoo}
];

...

function myTest(injector: Injector) {
  var foo = injector.get(Foo);
  // This line used to work since `foo` used to be `any` before this
  // change, it will now be `Foo`, and `Foo` does not have `setUpMock()`.
  // The fix is to downcast: `injector.get(Foo) as MockFoo`.
  foo.setUpMock();
}
```

PR Close #13785
2017-01-17 15:34:54 -06:00

65 lines
1.9 KiB
TypeScript

/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {InjectionToken} from './di';
import {ComponentRef} from './linker/component_factory';
/**
* A DI Token representing a unique string id assigned to the application by Angular and used
* primarily for prefixing application attributes and CSS styles when
* {@link ViewEncapsulation#Emulated} is being used.
*
* If you need to avoid randomly generated value to be used as an application id, you can provide
* a custom value via a DI provider <!-- TODO: provider --> configuring the root {@link Injector}
* using this token.
* @experimental
*/
export const APP_ID = new InjectionToken<string>('AppId');
export function _appIdRandomProviderFactory() {
return `${_randomChar()}${_randomChar()}${_randomChar()}`;
}
/**
* Providers that will generate a random APP_ID_TOKEN.
* @experimental
*/
export const APP_ID_RANDOM_PROVIDER = {
provide: APP_ID,
useFactory: _appIdRandomProviderFactory,
deps: <any[]>[],
};
function _randomChar(): string {
return String.fromCharCode(97 + Math.floor(Math.random() * 25));
}
/**
* A function that will be executed when a platform is initialized.
* @experimental
*/
export const PLATFORM_INITIALIZER = new InjectionToken<Array<() => void>>('Platform Initializer');
/**
* All callbacks provided via this token will be called for every component that is bootstrapped.
* Signature of the callback:
*
* `(componentRef: ComponentRef) => void`.
*
* @experimental
*/
export const APP_BOOTSTRAP_LISTENER =
new InjectionToken<Array<(compRef: ComponentRef<any>) => void>>('appBootstrapListener');
/**
* A token which indicates the root directory of the application
* @experimental
*/
export const PACKAGE_ROOT_URL = new InjectionToken<string>('Application Packages Root URL');