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angular 2.0_typescript

angular

forwardRef

Experimental Function

Class Export

export forwardRef(forwardRefFn: ForwardRefFn) : Type<any>

Allows to refer to references which are not yet defined.

For instance, forwardRef is used when the token which we need to refer to for the purposes of DI is declared, but not yet defined. It is also used when the token which we use when creating a query is not yet defined.

Example

class Door {
  lock: Lock;

  // Door attempts to inject Lock, despite it not being defined yet.
  // forwardRef makes this possible.
  constructor(@Inject(forwardRef(() => Lock)) lock: Lock) { this.lock = lock; }
}

// Only at this point Lock is defined.
class Lock {}

let injector = ReflectiveInjector.resolveAndCreate([Door, Lock]);
let door = injector.get(Door);
expect(door instanceof Door).toBeTruthy();
expect(door.lock instanceof Lock).toBeTruthy();

exported from @angular/core/index defined in @angular/core/src/di/forward_ref.ts

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Licensed under the Creative Commons Attribution License 4.0.
https://angular.io/docs/ts/latest/api/core/index/forwardRef-function.html