angular-docs-cn/packages/common/test/directives/ng_switch_spec.ts

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/**
* @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 {CommonModule} from '@angular/common';
import {Attribute, Component, Directive, TemplateRef, ViewChild} from '@angular/core';
import {ComponentFixture, TestBed} from '@angular/core/testing';
import {expect} from '@angular/platform-browser/testing/src/matchers';
{
describe('NgSwitch', () => {
let fixture: ComponentFixture<any>;
function getComponent(): TestComponent { return fixture.componentInstance; }
function detectChangesAndExpectText(text: string): void {
fixture.detectChanges();
expect(fixture.nativeElement).toHaveText(text);
}
afterEach(() => { fixture = null !; });
beforeEach(() => {
TestBed.configureTestingModule({
declarations: [TestComponent, ComplexComponent],
imports: [CommonModule],
});
});
describe('switch value changes', () => {
it('should switch amongst when values', () => {
const template = '<ul [ngSwitch]="switchValue">' +
'<li *ngSwitchCase="\'a\'">when a</li>' +
'<li *ngSwitchCase="\'b\'">when b</li>' +
'</ul>';
fixture = createTestComponent(template);
detectChangesAndExpectText('');
getComponent().switchValue = 'a';
detectChangesAndExpectText('when a');
getComponent().switchValue = 'b';
detectChangesAndExpectText('when b');
});
it('should switch amongst when values with fallback to default', () => {
const template = '<ul [ngSwitch]="switchValue">' +
'<li *ngSwitchCase="\'a\'">when a</li>' +
'<li *ngSwitchDefault>when default</li>' +
'</ul>';
fixture = createTestComponent(template);
detectChangesAndExpectText('when default');
getComponent().switchValue = 'a';
detectChangesAndExpectText('when a');
getComponent().switchValue = 'b';
detectChangesAndExpectText('when default');
getComponent().switchValue = 'c';
detectChangesAndExpectText('when default');
});
it('should support multiple whens with the same value', () => {
const template = '<ul [ngSwitch]="switchValue">' +
'<li *ngSwitchCase="\'a\'">when a1;</li>' +
'<li *ngSwitchCase="\'b\'">when b1;</li>' +
'<li *ngSwitchCase="\'a\'">when a2;</li>' +
'<li *ngSwitchCase="\'b\'">when b2;</li>' +
'<li *ngSwitchDefault>when default1;</li>' +
'<li *ngSwitchDefault>when default2;</li>' +
'</ul>';
fixture = createTestComponent(template);
detectChangesAndExpectText('when default1;when default2;');
getComponent().switchValue = 'a';
detectChangesAndExpectText('when a1;when a2;');
getComponent().switchValue = 'b';
detectChangesAndExpectText('when b1;when b2;');
});
});
describe('when values changes', () => {
it('should switch amongst when values', () => {
const template = '<ul [ngSwitch]="switchValue">' +
'<li *ngSwitchCase="when1">when 1;</li>' +
'<li *ngSwitchCase="when2">when 2;</li>' +
'<li *ngSwitchDefault>when default;</li>' +
'</ul>';
fixture = createTestComponent(template);
getComponent().when1 = 'a';
getComponent().when2 = 'b';
getComponent().switchValue = 'a';
detectChangesAndExpectText('when 1;');
getComponent().switchValue = 'b';
detectChangesAndExpectText('when 2;');
getComponent().switchValue = 'c';
detectChangesAndExpectText('when default;');
getComponent().when1 = 'c';
detectChangesAndExpectText('when 1;');
getComponent().when1 = 'd';
detectChangesAndExpectText('when default;');
});
});
describe('corner cases', () => {
it('should not create the default case if another case matches', () => {
const log: string[] = [];
@Directive({selector: '[test]'})
class TestDirective {
constructor(@Attribute('test') test: string) { log.push(test); }
}
const template = '<div [ngSwitch]="switchValue">' +
'<div *ngSwitchCase="\'a\'" test="aCase"></div>' +
'<div *ngSwitchDefault test="defaultCase"></div>' +
'</div>';
TestBed.configureTestingModule({declarations: [TestDirective]});
const fixture = createTestComponent(template);
fixture.componentInstance.switchValue = 'a';
fixture.detectChanges();
expect(log).toEqual(['aCase']);
});
it('should create the default case if there is no other case', () => {
const template = '<ul [ngSwitch]="switchValue">' +
'<li *ngSwitchDefault>when default1;</li>' +
'<li *ngSwitchDefault>when default2;</li>' +
'</ul>';
fixture = createTestComponent(template);
detectChangesAndExpectText('when default1;when default2;');
});
it('should allow defaults before cases', () => {
const template = '<ul [ngSwitch]="switchValue">' +
'<li *ngSwitchDefault>when default1;</li>' +
'<li *ngSwitchDefault>when default2;</li>' +
'<li *ngSwitchCase="\'a\'">when a1;</li>' +
'<li *ngSwitchCase="\'b\'">when b1;</li>' +
'<li *ngSwitchCase="\'a\'">when a2;</li>' +
'<li *ngSwitchCase="\'b\'">when b2;</li>' +
'</ul>';
fixture = createTestComponent(template);
detectChangesAndExpectText('when default1;when default2;');
getComponent().switchValue = 'a';
detectChangesAndExpectText('when a1;when a2;');
getComponent().switchValue = 'b';
detectChangesAndExpectText('when b1;when b2;');
});
it('should support nested NgSwitch on ng-container with ngTemplateOutlet', () => {
fixture = TestBed.createComponent(ComplexComponent);
detectChangesAndExpectText('Foo');
fixture.componentInstance.state = 'case2';
detectChangesAndExpectText('Bar');
fixture.componentInstance.state = 'notACase';
detectChangesAndExpectText('Default');
fixture.componentInstance.state = 'case1';
detectChangesAndExpectText('Foo');
});
});
});
}
@Component({selector: 'test-cmp', template: ''})
class TestComponent {
switchValue: any = null;
when1: any = null;
when2: any = null;
}
@Component({
selector: 'complex-cmp',
template: `
<div [ngSwitch]="state">
<ng-container *ngSwitchCase="'case1'" [ngSwitch]="true">
<ng-container *ngSwitchCase="true" [ngTemplateOutlet]="foo"></ng-container>
<span *ngSwitchDefault>Should never render</span>
</ng-container>
<ng-container *ngSwitchCase="'case2'" [ngSwitch]="true">
<ng-container *ngSwitchCase="true" [ngTemplateOutlet]="bar"></ng-container>
<span *ngSwitchDefault>Should never render</span>
</ng-container>
<ng-container *ngSwitchDefault [ngSwitch]="false">
<ng-container *ngSwitchCase="true" [ngTemplateOutlet]="foo"></ng-container>
<span *ngSwitchDefault>Default</span>
</ng-container>
</div>
<ng-template #foo>
<span>Foo</span>
</ng-template>
<ng-template #bar>
<span>Bar</span>
</ng-template>
`
})
class ComplexComponent {
@ViewChild('foo', {static: true}) foo !: TemplateRef<any>;
@ViewChild('bar', {static: true}) bar !: TemplateRef<any>;
state: string = 'case1';
}
function createTestComponent(template: string): ComponentFixture<TestComponent> {
return TestBed.overrideComponent(TestComponent, {set: {template: template}})
.createComponent(TestComponent);
}