angular/modules/@angular/core/src/application_init.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

50 lines
1.3 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 {isPromise} from '../src/util/lang';
import {Inject, Injectable, InjectionToken, Optional} from './di';
/**
* A function that will be executed when an application is initialized.
* @experimental
*/
export const APP_INITIALIZER = new InjectionToken<Array<() => void>>('Application Initializer');
/**
* A class that reflects the state of running {@link APP_INITIALIZER}s.
*
* @experimental
*/
@Injectable()
export class ApplicationInitStatus {
private _donePromise: Promise<any>;
private _done = false;
constructor(@Inject(APP_INITIALIZER) @Optional() appInits: (() => any)[]) {
const asyncInitPromises: Promise<any>[] = [];
if (appInits) {
for (let i = 0; i < appInits.length; i++) {
const initResult = appInits[i]();
if (isPromise(initResult)) {
asyncInitPromises.push(initResult);
}
}
}
this._donePromise = Promise.all(asyncInitPromises).then(() => { this._done = true; });
if (asyncInitPromises.length === 0) {
this._done = true;
}
}
get done(): boolean { return this._done; }
get donePromise(): Promise<any> { return this._donePromise; }
}