refactor: remove ToastInjector in favor of creating an instance via I…

…njector.create

This commit removes a custom ToastInjector (that provided a single token) in favor of creating a new injector instance using the `Injector.create` call.

The goal of this change is to make the library forward-compatible with an upcoming change to the Injector interface, see angular/angular#46761.

src/lib/toastr/toast-injector.ts

@@ -1,7 +1,5 @@
-import { Injector, InjectFlags } from '@angular/core';
 import { Observable, Subject } from 'rxjs';
 import { OverlayRef } from '../overlay/overlay-ref';
-import { ToastPackage } from './toastr-config';
 
 /**
  * Reference to a toast opened via the Toastr service.
@@ -86,18 +84,3 @@ export class ToastRef<T> {
     }
   }
 }
-
-/** Custom injector type specifically for instantiating components with a toast. */
-export class ToastInjector implements Injector {
-  constructor(
-    private _toastPackage: ToastPackage,
-    private _parentInjector: Injector
-  ) {}
-
-  get<T>(token: any, notFoundValue?: T, flags?: InjectFlags): T | ToastPackage {
-    if (token === ToastPackage) {
-      return this._toastPackage;
-    }
-    return this._parentInjector.get<T>(token, notFoundValue, flags);
-  }
-}

src/lib/toastr/toastr.service.ts

@@ -5,7 +5,7 @@ import { Observable } from 'rxjs';
 
 import { Overlay } from '../overlay/overlay';
 import { ComponentPortal } from '../portal/portal';
-import { ToastInjector, ToastRef } from './toast-injector';
+import { ToastRef } from './toast-injector';
 import { ToastContainerDirective } from './toast.directive';
 import {
   GlobalConfig,
@@ -231,7 +231,11 @@ export class ToastrService {
       toastType,
       toastRef,
     );
-    const toastInjector = new ToastInjector(toastPackage, this._injector);
+
+    /** New injector that contains an instance of `ToastPackage`. */
+    const providers = [{provide: ToastPackage, useValue: toastPackage}];
+    const toastInjector = Injector.create({providers, parent: this._injector});
+
     const component = new ComponentPortal(config.toastComponent, toastInjector);
     const portal = overlayRef.attach(component, this.toastrConfig.newestOnTop);
     toastRef.componentInstance = portal.instance;