- 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
		
	
			
		
			
				
	
	
		
			50 lines
		
	
	
		
			1.3 KiB
		
	
	
	
		
			TypeScript
		
	
	
	
	
	
			
		
		
	
	
			50 lines
		
	
	
		
			1.3 KiB
		
	
	
	
		
			TypeScript
		
	
	
	
	
	
/**
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 * @license
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 * Copyright Google Inc. All Rights Reserved.
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 *
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 * Use of this source code is governed by an MIT-style license that can be
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 * found in the LICENSE file at https://angular.io/license
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 */
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import {isPromise} from '../src/util/lang';
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import {Inject, Injectable, InjectionToken, Optional} from './di';
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/**
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 * A function that will be executed when an application is initialized.
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 * @experimental
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 */
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export const APP_INITIALIZER = new InjectionToken<Array<() => void>>('Application Initializer');
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/**
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 * A class that reflects the state of running {@link APP_INITIALIZER}s.
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 *
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 * @experimental
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 */
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@Injectable()
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export class ApplicationInitStatus {
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  private _donePromise: Promise<any>;
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  private _done = false;
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  constructor(@Inject(APP_INITIALIZER) @Optional() appInits: (() => any)[]) {
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    const asyncInitPromises: Promise<any>[] = [];
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    if (appInits) {
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      for (let i = 0; i < appInits.length; i++) {
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        const initResult = appInits[i]();
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        if (isPromise(initResult)) {
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          asyncInitPromises.push(initResult);
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        }
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      }
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    }
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    this._donePromise = Promise.all(asyncInitPromises).then(() => { this._done = true; });
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    if (asyncInitPromises.length === 0) {
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      this._done = true;
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    }
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  }
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  get done(): boolean { return this._done; }
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  get donePromise(): Promise<any> { return this._donePromise; }
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}
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