feat(router): add prioritizedGuardValue operator optimization and allowing UrlTree return from guard (#26478)

* If all guards return `true`, operator returns `true`
* `false` and `UrlTree` are now both valid returns from a guard
* Both these values wait for higher priority guards to resolve
* Highest priority `false` or `UrlTree` value will be returned

PR Close #26478

packages/router/test/operators/prioritized_guard_value.spec.ts

@@ -0,0 +1,182 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+
+import {TestBed} from '@angular/core/testing';
+import {Observable, Observer, of } from 'rxjs';
+import {every, mergeMap} from 'rxjs/operators';
+import {TestScheduler} from 'rxjs/testing';
+
+import {prioritizedGuardValue} from '../../src/operators/prioritized_guard_value';
+import {Router} from '../../src/router';
+import {UrlTree} from '../../src/url_tree';
+import {RouterTestingModule} from '../../testing/src/router_testing_module';
+
+
+describe('prioritizedGuardValue operator', () => {
+  let testScheduler: TestScheduler;
+  let router: Router;
+  const TF = {T: true, F: false};
+
+  beforeEach(() => { TestBed.configureTestingModule({imports: [RouterTestingModule]}); });
+  beforeEach(() => { testScheduler = new TestScheduler(assertDeepEquals); });
+  beforeEach(() => { router = TestBed.get(Router); });
+
+  it('should return true if all values are true', () => {
+    testScheduler.run(({hot, cold, expectObservable}) => {
+
+      const a = cold('       --(T|)', TF);
+      const b = cold('       ----------(T|)', TF);
+      const c = cold('       ------(T|)', TF);
+      const source = hot('---o--', {o: [a, b, c]});
+
+      const expected = '  -------------T--';
+
+      expectObservable(source.pipe(prioritizedGuardValue()))
+          .toBe(expected, TF, /* an error here maybe */);
+    });
+  });
+
+  it('should return false if observables to the left of false have produced a value', () => {
+    testScheduler.run(({hot, cold, expectObservable}) => {
+
+      const a = cold('       --(T|)', TF);
+      const b = cold('       ----------(T|)', TF);
+      const c = cold('       ------(F|)', TF);
+      const source = hot('---o--', {o: [a, b, c]});
+
+      const expected = '  -------------F--';
+
+      expectObservable(source.pipe(prioritizedGuardValue()))
+          .toBe(expected, TF, /* an error here maybe */);
+    });
+  });
+
+  it('should ignore results for unresolved sets of Observables', () => {
+    testScheduler.run(({hot, cold, expectObservable}) => {
+
+      const a = cold('       --(T|)', TF);
+      const b = cold('       -------------(T|)', TF);
+      const c = cold('       ------(F|)', TF);
+
+      const z = cold('            ----(T|)', TF);
+
+      const source = hot('---o----p----', {o: [a, b, c], p: [z]});
+
+      const expected = '  ------------T---';
+
+      expectObservable(source.pipe(prioritizedGuardValue()))
+          .toBe(expected, TF, /* an error here maybe */);
+    });
+  });
+
+  it('should return UrlTree if higher priority guards have resolved', () => {
+    testScheduler.run(({hot, cold, expectObservable}) => {
+
+      const urlTree = router.parseUrl('/');
+
+      const urlLookup = {U: urlTree};
+
+      const a = cold('       --(T|)', TF);
+      const b = cold('       ----------(U|)', urlLookup);
+      const c = cold('       ------(T|)', TF);
+
+      const source = hot('---o---', {o: [a, b, c]});
+
+      const expected = '  -------------U---';
+
+      expectObservable(source.pipe(prioritizedGuardValue()))
+          .toBe(expected, urlLookup, /* an error here maybe */);
+    });
+  });
+
+  it('should return false even with UrlTree if UrlTree is lower priority', () => {
+    testScheduler.run(({hot, cold, expectObservable}) => {
+
+      const urlTree = router.parseUrl('/');
+
+      const urlLookup = {U: urlTree};
+
+      const a = cold('       --(T|)', TF);
+      const b = cold('       ----------(F|)', TF);
+      const c = cold('       ------(U|)', urlLookup);
+
+      const source = hot('---o---', {o: [a, b, c]});
+
+      const expected = '  -------------F---';
+
+      expectObservable(source.pipe(prioritizedGuardValue()))
+          .toBe(expected, TF, /* an error here maybe */);
+    });
+  });
+
+  it('should return UrlTree even after a false if the false is lower priority', () => {
+    testScheduler.run(({hot, cold, expectObservable}) => {
+
+      const urlTree = router.parseUrl('/');
+
+      const urlLookup = {U: urlTree};
+
+      const a = cold('       --(T|)', TF);
+      const b = cold('       ----------(U|)', urlLookup);
+      const c = cold('       ------(F|)', TF);
+
+      const source = hot('---o---', {o: [a, b, c]});
+
+      const expected = '  -------------U----';
+
+      expectObservable(source.pipe(prioritizedGuardValue()))
+          .toBe(expected, urlLookup, /* an error here maybe */);
+    });
+  });
+
+  it('should return the highest priority UrlTree', () => {
+    testScheduler.run(({hot, cold, expectObservable}) => {
+
+      const urlTreeU = router.parseUrl('/u');
+      const urlTreeR = router.parseUrl('/r');
+      const urlTreeL = router.parseUrl('/l');
+
+      const urlLookup = {U: urlTreeU, R: urlTreeR, L: urlTreeL};
+
+      const a = cold('       ----------(U|)', urlLookup);
+      const b = cold('       -----(R|)', urlLookup);
+      const c = cold('       --(L|)', urlLookup);
+
+      const source = hot('---o---', {o: [a, b, c]});
+
+      const expected = '  -------------U---';
+
+      expectObservable(source.pipe(prioritizedGuardValue()))
+          .toBe(expected, urlLookup, /* an error here maybe */);
+    });
+  });
+
+  it('should propagate errors', () => {
+    testScheduler.run(({hot, cold, expectObservable}) => {
+
+      const a = cold('       --(T|)', TF);
+      const b = cold('       ------#', TF);
+      const c = cold('       ----------(F|)', TF);
+      const source = hot('---o------', {o: [a, b, c]});
+
+      const expected = '  ---------#';
+
+      expectObservable(source.pipe(prioritizedGuardValue()))
+          .toBe(expected, TF, /* an error here maybe */);
+    });
+  });
+
+
+});
+
+
+
+function assertDeepEquals(a: any, b: any) {
+  return expect(a).toEqual(b);
+}