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

413 lines
15 KiB
TypeScript

/**
* @license
* Copyright Google LLC 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 {Component} from '@angular/core';
import {ComponentFixture, TestBed, waitForAsync} from '@angular/core/testing';
import {By} from '@angular/platform-browser/src/dom/debug/by';
import {expect} from '@angular/platform-browser/testing/src/matchers';
let thisArg: any;
{
describe('ngFor', () => {
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 as any;
});
beforeEach(() => {
TestBed.configureTestingModule({
declarations: [TestComponent],
imports: [CommonModule],
});
});
it('should reflect initial elements', waitForAsync(() => {
fixture = createTestComponent();
detectChangesAndExpectText('1;2;');
}));
it('should reflect added elements', waitForAsync(() => {
fixture = createTestComponent();
fixture.detectChanges();
getComponent().items.push(3);
detectChangesAndExpectText('1;2;3;');
}));
it('should reflect removed elements', waitForAsync(() => {
fixture = createTestComponent();
fixture.detectChanges();
getComponent().items.splice(1, 1);
detectChangesAndExpectText('1;');
}));
it('should reflect moved elements', waitForAsync(() => {
fixture = createTestComponent();
fixture.detectChanges();
getComponent().items.splice(0, 1);
getComponent().items.push(1);
detectChangesAndExpectText('2;1;');
}));
it('should reflect a mix of all changes (additions/removals/moves)', waitForAsync(() => {
fixture = createTestComponent();
getComponent().items = [0, 1, 2, 3, 4, 5];
fixture.detectChanges();
getComponent().items = [6, 2, 7, 0, 4, 8];
detectChangesAndExpectText('6;2;7;0;4;8;');
}));
it('should iterate over an array of objects', waitForAsync(() => {
const template = '<ul><li *ngFor="let item of items">{{item["name"]}};</li></ul>';
fixture = createTestComponent(template);
// INIT
getComponent().items = [{'name': 'misko'}, {'name': 'shyam'}];
detectChangesAndExpectText('misko;shyam;');
// GROW
getComponent().items.push({'name': 'adam'});
detectChangesAndExpectText('misko;shyam;adam;');
// SHRINK
getComponent().items.splice(2, 1);
getComponent().items.splice(0, 1);
detectChangesAndExpectText('shyam;');
}));
it('should gracefully handle nulls', waitForAsync(() => {
const template = '<ul><li *ngFor="let item of null">{{item}};</li></ul>';
fixture = createTestComponent(template);
detectChangesAndExpectText('');
}));
it('should gracefully handle ref changing to null and back', waitForAsync(() => {
fixture = createTestComponent();
detectChangesAndExpectText('1;2;');
getComponent().items = null!;
detectChangesAndExpectText('');
getComponent().items = [1, 2, 3];
detectChangesAndExpectText('1;2;3;');
}));
it('should throw on non-iterable ref and suggest using an array', waitForAsync(() => {
fixture = createTestComponent();
getComponent().items = <any>'whaaa';
expect(() => fixture.detectChanges())
.toThrowError(
/Cannot find a differ supporting object 'whaaa' of type 'string'. NgFor only supports binding to Iterables such as Arrays/);
}));
it('should throw on ref changing to string', waitForAsync(() => {
fixture = createTestComponent();
detectChangesAndExpectText('1;2;');
getComponent().items = <any>'whaaa';
expect(() => fixture.detectChanges()).toThrowError();
}));
it('should works with duplicates', waitForAsync(() => {
fixture = createTestComponent();
const a = new Foo();
getComponent().items = [a, a];
detectChangesAndExpectText('foo;foo;');
}));
it('should repeat over nested arrays', waitForAsync(() => {
const template = '<div *ngFor="let item of items">' +
'<div *ngFor="let subitem of item">{{subitem}}-{{item.length}};</div>|' +
'</div>';
fixture = createTestComponent(template);
getComponent().items = [['a', 'b'], ['c']];
detectChangesAndExpectText('a-2;b-2;|c-1;|');
getComponent().items = [['e'], ['f', 'g']];
detectChangesAndExpectText('e-1;|f-2;g-2;|');
}));
it('should repeat over nested arrays with no intermediate element', waitForAsync(() => {
const template = '<div *ngFor="let item of items">' +
'<div *ngFor="let subitem of item">{{subitem}}-{{item.length}};</div>' +
'</div>';
fixture = createTestComponent(template);
getComponent().items = [['a', 'b'], ['c']];
detectChangesAndExpectText('a-2;b-2;c-1;');
getComponent().items = [['e'], ['f', 'g']];
detectChangesAndExpectText('e-1;f-2;g-2;');
}));
it('should repeat over nested ngIf that are the last node in the ngFor template',
waitForAsync(() => {
const template = `<div *ngFor="let item of items; let i=index">` +
`<div>{{i}}|</div>` +
`<div *ngIf="i % 2 == 0">even|</div>` +
`</div>`;
fixture = createTestComponent(template);
const items = [1];
getComponent().items = items;
detectChangesAndExpectText('0|even|');
items.push(1);
detectChangesAndExpectText('0|even|1|');
items.push(1);
detectChangesAndExpectText('0|even|1|2|even|');
}));
it('should allow of saving the collection', waitForAsync(() => {
const template =
'<ul><li *ngFor="let item of items as collection; index as i">{{i}}/{{collection.length}} - {{item}};</li></ul>';
fixture = createTestComponent(template);
detectChangesAndExpectText('0/2 - 1;1/2 - 2;');
getComponent().items = [1, 2, 3];
detectChangesAndExpectText('0/3 - 1;1/3 - 2;2/3 - 3;');
}));
it('should display indices correctly', waitForAsync(() => {
const template = '<span *ngFor ="let item of items; let i=index">{{i.toString()}}</span>';
fixture = createTestComponent(template);
getComponent().items = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
detectChangesAndExpectText('0123456789');
getComponent().items = [1, 2, 6, 7, 4, 3, 5, 8, 9, 0];
detectChangesAndExpectText('0123456789');
}));
it('should display count correctly', waitForAsync(() => {
const template = '<span *ngFor="let item of items; let len=count">{{len}}</span>';
fixture = createTestComponent(template);
getComponent().items = [0, 1, 2];
detectChangesAndExpectText('333');
getComponent().items = [4, 3, 2, 1, 0, -1];
detectChangesAndExpectText('666666');
}));
it('should display first item correctly', waitForAsync(() => {
const template =
'<span *ngFor="let item of items; let isFirst=first">{{isFirst.toString()}}</span>';
fixture = createTestComponent(template);
getComponent().items = [0, 1, 2];
detectChangesAndExpectText('truefalsefalse');
getComponent().items = [2, 1];
detectChangesAndExpectText('truefalse');
}));
it('should display last item correctly', waitForAsync(() => {
const template =
'<span *ngFor="let item of items; let isLast=last">{{isLast.toString()}}</span>';
fixture = createTestComponent(template);
getComponent().items = [0, 1, 2];
detectChangesAndExpectText('falsefalsetrue');
getComponent().items = [2, 1];
detectChangesAndExpectText('falsetrue');
}));
it('should display even items correctly', waitForAsync(() => {
const template =
'<span *ngFor="let item of items; let isEven=even">{{isEven.toString()}}</span>';
fixture = createTestComponent(template);
getComponent().items = [0, 1, 2];
detectChangesAndExpectText('truefalsetrue');
getComponent().items = [2, 1];
detectChangesAndExpectText('truefalse');
}));
it('should display odd items correctly', waitForAsync(() => {
const template =
'<span *ngFor="let item of items; let isOdd=odd">{{isOdd.toString()}}</span>';
fixture = createTestComponent(template);
getComponent().items = [0, 1, 2, 3];
detectChangesAndExpectText('falsetruefalsetrue');
getComponent().items = [2, 1];
detectChangesAndExpectText('falsetrue');
}));
it('should allow to use a custom template', waitForAsync(() => {
const template =
'<ng-container *ngFor="let item of items; template: tpl"></ng-container>' +
'<ng-template let-item let-i="index" #tpl><p>{{i}}: {{item}};</p></ng-template>';
fixture = createTestComponent(template);
getComponent().items = ['a', 'b', 'c'];
fixture.detectChanges();
detectChangesAndExpectText('0: a;1: b;2: c;');
}));
it('should use a default template if a custom one is null', waitForAsync(() => {
const template =
`<ul><ng-container *ngFor="let item of items; template: null; let i=index">{{i}}: {{item}};</ng-container></ul>`;
fixture = createTestComponent(template);
getComponent().items = ['a', 'b', 'c'];
fixture.detectChanges();
detectChangesAndExpectText('0: a;1: b;2: c;');
}));
it('should use a custom template when both default and a custom one are present',
waitForAsync(() => {
const template =
'<ng-container *ngFor="let item of items; template: tpl">{{i}};</ng-container>' +
'<ng-template let-item let-i="index" #tpl>{{i}}: {{item}};</ng-template>';
fixture = createTestComponent(template);
getComponent().items = ['a', 'b', 'c'];
fixture.detectChanges();
detectChangesAndExpectText('0: a;1: b;2: c;');
}));
describe('track by', () => {
it('should console.warn if trackBy is not a function', waitForAsync(() => {
// TODO(vicb): expect a warning message when we have a proper log service
const template = `<p *ngFor="let item of items; trackBy: value"></p>`;
fixture = createTestComponent(template);
fixture.componentInstance.value = 0;
fixture.detectChanges();
}));
it('should track by identity when trackBy is to `null` or `undefined`', waitForAsync(() => {
// TODO(vicb): expect no warning message when we have a proper log service
const template = `<p *ngFor="let item of items; trackBy: value">{{ item }}</p>`;
fixture = createTestComponent(template);
fixture.componentInstance.items = ['a', 'b', 'c'];
fixture.componentInstance.value = null;
detectChangesAndExpectText('abc');
fixture.componentInstance.value = undefined;
detectChangesAndExpectText('abc');
}));
it('should set the context to the component instance', waitForAsync(() => {
const template =
`<p *ngFor="let item of items; trackBy: trackByContext.bind(this)"></p>`;
fixture = createTestComponent(template);
thisArg = null;
fixture.detectChanges();
expect(thisArg).toBe(getComponent());
}));
it('should not replace tracked items', waitForAsync(() => {
const template =
`<p *ngFor="let item of items; trackBy: trackById; let i=index">{{items[i]}}</p>`;
fixture = createTestComponent(template);
const buildItemList = () => {
getComponent().items = [{'id': 'a'}];
fixture.detectChanges();
return fixture.debugElement.queryAll(By.css('p'))[0];
};
const firstP = buildItemList();
const finalP = buildItemList();
expect(finalP.nativeElement).toBe(firstP.nativeElement);
}));
it('should update implicit local variable on view', waitForAsync(() => {
const template =
`<div *ngFor="let item of items; trackBy: trackById">{{item['color']}}</div>`;
fixture = createTestComponent(template);
getComponent().items = [{'id': 'a', 'color': 'blue'}];
detectChangesAndExpectText('blue');
getComponent().items = [{'id': 'a', 'color': 'red'}];
detectChangesAndExpectText('red');
}));
it('should move items around and keep them updated ', waitForAsync(() => {
const template =
`<div *ngFor="let item of items; trackBy: trackById">{{item['color']}}</div>`;
fixture = createTestComponent(template);
getComponent().items = [{'id': 'a', 'color': 'blue'}, {'id': 'b', 'color': 'yellow'}];
detectChangesAndExpectText('blueyellow');
getComponent().items = [{'id': 'b', 'color': 'orange'}, {'id': 'a', 'color': 'red'}];
detectChangesAndExpectText('orangered');
}));
it('should handle added and removed items properly when tracking by index',
waitForAsync(() => {
const template = `<div *ngFor="let item of items; trackBy: trackByIndex">{{item}}</div>`;
fixture = createTestComponent(template);
getComponent().items = ['a', 'b', 'c', 'd'];
fixture.detectChanges();
getComponent().items = ['e', 'f', 'g', 'h'];
fixture.detectChanges();
getComponent().items = ['e', 'f', 'h'];
detectChangesAndExpectText('efh');
}));
});
});
}
class Foo {
toString() {
return 'foo';
}
}
@Component({selector: 'test-cmp', template: ''})
class TestComponent {
value: any;
items: any[] = [1, 2];
trackById(index: number, item: any): string {
return item['id'];
}
trackByIndex(index: number, item: any): number {
return index;
}
trackByContext(): void {
thisArg = this;
}
}
const TEMPLATE = '<div><span *ngFor="let item of items">{{item.toString()}};</span></div>';
function createTestComponent(template: string = TEMPLATE): ComponentFixture<TestComponent> {
return TestBed.overrideComponent(TestComponent, {set: {template: template}})
.createComponent(TestComponent);
}