feat(cart): add daffCartDriverHandleCartNotFound (#2489)

libs/cart/driver/src/operators/handle-cart-not-found.spec.ts

@@ -0,0 +1,112 @@
+import {
+  Observable,
+  Subject,
+  catchError,
+  of,
+} from 'rxjs';
+
+import { DaffCartStorageService } from '@daffodil/cart';
+import { DaffCartNotFoundError } from '@daffodil/cart/driver';
+
+import { daffCartDriverHandleCartNotFound } from './handle-cart-not-found';
+
+describe('@daffodil/cart/driver | daffCartDriverHandleCartNotFound', () => {
+  let source: Subject<any>;
+  let result: Observable<any>;
+  let cartStorageSpy: jasmine.SpyObj<DaffCartStorageService>;
+
+  beforeEach(() => {
+    source = new Subject();
+    cartStorageSpy = jasmine.createSpyObj('DaffCartStorageService', ['removeCartId']);
+    result = source.pipe(
+      daffCartDriverHandleCartNotFound(cartStorageSpy),
+    );
+  });
+
+  describe('when the source emits a value', () => {
+    let value: number;
+
+    beforeEach(() => {
+      value = 5;
+    });
+
+    it('should pass that value through', (done) => {
+      result.pipe(
+        catchError((err) => {
+          fail('should not throw');
+          return of();
+        }),
+      ).subscribe((res) => {
+        expect(res).toEqual(value);
+        done();
+      });
+      source.next(5);
+    });
+  });
+
+  describe('when the source throws a generic error', () => {
+    let error: Error;
+
+    beforeEach(() => {
+      error = new Error('');
+      source.error(error);
+    });
+
+    it('should throw that error', (done) => {
+      result.pipe(
+        catchError((err) => {
+          expect(err).toEqual(error);
+          done();
+          return of();
+        }),
+      ).subscribe((res) => {
+        fail('should not emit');
+      });
+    });
+
+    it('should not remove cart ID from storage', (done) => {
+      result.pipe(
+        catchError((err) => {
+          expect(cartStorageSpy.removeCartId).not.toHaveBeenCalled();
+          done();
+          return of();
+        }),
+      ).subscribe((res) => {
+        fail('should not emit');
+      });
+    });
+  });
+
+  describe('when the source throws a cart not found error', () => {
+    let error: DaffCartNotFoundError;
+
+    beforeEach(() => {
+      error = new DaffCartNotFoundError('');
+      source.error(error);
+    });
+
+    it('should throw that error', (done) => {
+      result.pipe(
+        catchError((err) => {
+          expect(err).toEqual(error);
+          done();
+          return of();
+        }),
+      ).subscribe((res) => {
+        fail('should not emit');
+      });
+    });
+
+    it('should remove cart ID from storage', (done) => {
+      result.pipe(
+        catchError((err) => {
+          expect(cartStorageSpy.removeCartId).toHaveBeenCalledWith();
+          done();
+          return of();
+        }),
+      ).subscribe((res) => {
+        fail('should not emit');
+      });
+    });
+  });
+});

libs/cart/driver/src/operators/handle-cart-not-found.ts

@@ -0,0 +1,28 @@
+import {
+  Observable,
+  catchError,
+  pipe,
+  throwError,
+} from 'rxjs';
+
+import { DaffCartStorageService } from '@daffodil/cart';
+
+import { DaffCartNotFoundError } from '../errors/public_api';
+
+/**
+ * If a {@link DaffCartNotFoundError} is thrown into the stream,
+ * the cart ID is removed from storage.
+ * All errors are thrown back into the stream.
+ */
+export const daffCartDriverHandleCartNotFound = <T>(storage: DaffCartStorageService) => pipe<Observable<T>, Observable<T>>(
+  catchError((error) => {
+    switch (true) {
+      case error instanceof DaffCartNotFoundError:
+        storage.removeCartId();
+        return throwError(() => error);
+
+      default:
+        return throwError(() => error);
+    }
+  }),
+);

libs/cart/driver/src/operators/public_api.ts

@@ -0,0 +1 @@
+export { daffCartDriverHandleCartNotFound } from './handle-cart-not-found';

libs/cart/driver/src/public_api.ts

@@ -1,3 +1,4 @@
 export * from './interfaces/public_api';
 export * from './injection-tokens/public_api';
 export * from './errors/public_api';
+export * from './operators/public_api';