fix(common): properly check NaN value (#22305)

closes #15721

PR Close #22305

packages/common/src/pipes/async_pipe.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {ChangeDetectorRef, EventEmitter, Injectable, OnDestroy, Pipe, PipeTransform, WrappedValue, ɵisObservable, ɵisPromise} from '@angular/core';
+import {ChangeDetectorRef, EventEmitter, Injectable, OnDestroy, Pipe, PipeTransform, WrappedValue, ɵisObservable, ɵisPromise, ɵlooseIdentical} from '@angular/core';
 import {Observable, SubscriptionLike} from 'rxjs';
 import {invalidPipeArgumentError} from './invalid_pipe_argument_error';
 
@@ -103,7 +103,7 @@ export class AsyncPipe implements OnDestroy, PipeTransform {
       return this.transform(obj as any);
     }
 
-    if (this._latestValue === this._latestReturnedValue) {
+    if (ɵlooseIdentical(this._latestValue, this._latestReturnedValue)) {
       return this._latestReturnedValue;
     }
 

packages/common/test/pipes/async_pipe_spec.ts

@@ -82,6 +82,18 @@ import {SpyChangeDetectorRef} from '../spies';
                async.done();
              }, 10);
            }));
+
+        it('should return unwrapped value for unchanged NaN', () => {
+          const emitter = new EventEmitter<any>();
+          emitter.emit(null);
+          pipe.transform(emitter);
+          emitter.next(NaN);
+          const firstResult = pipe.transform(emitter);
+          const secondResult = pipe.transform(emitter);
+          expect(firstResult instanceof WrappedValue).toBe(true);
+          expect((firstResult as WrappedValue).wrapped).toBeNaN();
+          expect(secondResult).toBeNaN();
+        });
       });
 
       describe('ngOnDestroy', () => {