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feat(router): add prioritizedGuardValue operator optimization and all…

…owing 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
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jasonaden authored and mhevery committed Oct 15, 2018
1 parent 9e5d440 commit fdfedceeecfd4fc2f4b8f1c01a23ecc41c93bcbe
@@ -0,0 +1,52 @@
/**
* @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 {Observable, OperatorFunction, combineLatest} from 'rxjs';
import {filter, scan, startWith, switchMap, take} from 'rxjs/operators';
import {UrlTree} from '../url_tree';
const INITIAL_VALUE = Symbol('INITIAL_VALUE');
declare type INTERIM_VALUES = typeof INITIAL_VALUE | boolean | UrlTree;
export function prioritizedGuardValue():
OperatorFunction<Observable<boolean|UrlTree>[], boolean|UrlTree> {
return switchMap(obs => {
return combineLatest(
...obs.map(o => o.pipe(take(1), startWith(INITIAL_VALUE as INTERIM_VALUES))))
.pipe(
scan(
(acc: INTERIM_VALUES, list: INTERIM_VALUES[]) => {
let isPending = false;
return list.reduce((innerAcc, val, i: number) => {
if (innerAcc !== INITIAL_VALUE) return innerAcc;
// Toggle pending flag if any values haven't been set yet
if (val === INITIAL_VALUE) isPending = true;
// Any other return values are only valid if we haven't yet hit a pending call.
// This guarantees that in the case of a guard at the bottom of the tree that
// returns a redirect, we will wait for the higher priority guard at the top to
// finish before performing the redirect.
if (!isPending) {
// Early return when we hit a `false` value as that should always cancel
// navigation
if (val === false) return val;
if (i === list.length - 1 || val instanceof UrlTree) {
return val;
}
}
return innerAcc;
}, acc);
},
INITIAL_VALUE),
filter(item => item !== INITIAL_VALUE), take(1)) as Observable<boolean|UrlTree>;
});
}
@@ -16,6 +16,7 @@ ts_library(
"//packages/router/testing",
"@rxjs",
"@rxjs//operators",
"@rxjs//testing",
],
)
@@ -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);
}

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