angular-docs-cn/packages/router/test/shared.spec.ts

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feat(router): introduce `ParamMap` to access parameters The Router use the type `Params` for all of: - position parameters, - matrix parameters, - query parameters. `Params` is defined as follow `type Params = {[key: string]: any}` Because parameters can either have single or multiple values, the type should actually be `type Params = {[key: string]: string | string[]}`. The client code often assumes that parameters have single values, as in the following exemple: ``` class MyComponent { sessionId: Observable<string>; constructor(private route: ActivatedRoute) {} ngOnInit() { this.sessionId = this.route .queryParams .map(params => params['session_id'] || 'None'); } } ``` The problem here is that `params['session_id']` could be `string` or `string[]` but the error is not caught at build time because of the `any` type. Fixing the type as describe above would break the build because `sessionId` would becomes an `Observable<string | string[]>`. However the client code knows if it expects a single or multiple values. By using the new `ParamMap` interface the user code can decide when it needs a single value (calling `ParamMap.get(): string`) or multiple values (calling `ParamMap.getAll(): string[]`). The above exemple should be rewritten as: ``` class MyComponent { sessionId: Observable<string>; constructor(private route: ActivatedRoute) {} ngOnInit() { this.sessionId = this.route .queryParamMap .map(paramMap => paramMap.get('session_id') || 'None'); } } ``` Added APIs: - `interface ParamMap`, - `ActivatedRoute.paramMap: ParamMap`, - `ActivatedRoute.queryParamMap: ParamMap`, - `ActivatedRouteSnapshot.paramMap: ParamMap`, - `ActivatedRouteSnapshot.queryParamMap: ParamMap`, - `UrlSegment.parameterMap: ParamMap`
2017-03-17 13:09:42 -04:00
/**
* @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 {ParamMap, convertToParamMap} from '../src/shared';
describe('ParamsMap', () => {
it('should returns whether a parameter is present', () => {
const map = convertToParamMap({single: 's', multiple: ['m1', 'm2']});
expect(map.has('single')).toEqual(true);
expect(map.has('multiple')).toEqual(true);
expect(map.has('not here')).toEqual(false);
});
it('should support single valued parameters', () => {
const map = convertToParamMap({single: 's', multiple: ['m1', 'm2']});
expect(map.get('single')).toEqual('s');
expect(map.get('multiple')).toEqual('m1');
});
it('should support multiple valued parameters', () => {
const map = convertToParamMap({single: 's', multiple: ['m1', 'm2']});
expect(map.getAll('single')).toEqual(['s']);
expect(map.getAll('multiple')).toEqual(['m1', 'm2']);
});
it('should return `null` when a single valued element is absent', () => {
const map = convertToParamMap({});
expect(map.get('name')).toEqual(null);
});
it('should return `[]` when a mulitple valued element is absent', () => {
const map = convertToParamMap({});
expect(map.getAll('name')).toEqual([]);
});
});