fix(Common): allow null/undefined values for NgForTrackBy
Reverts a breaking change introduced in 2.4.1 by #13420 fixes #13641
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committed by
Igor Minar

parent
504199cf5a
commit
6be55cc214
@ -294,14 +294,25 @@ export function main() {
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}));
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describe('track by', () => {
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it('should throw if trackBy is not a function', async(() => {
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it('should console.warn if trackBy is not a function', async(() => {
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// TODO(vicb): expect a warning message when we have a proper log service
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const template =
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`<template ngFor let-item [ngForOf]="items" [ngForTrackBy]="item?.id"></template>`;
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`<template ngFor let-item [ngForOf]="items" [ngForTrackBy]="value"></template>`;
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fixture = createTestComponent(template);
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fixture.componentInstance.value = 0;
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fixture.detectChanges();
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}));
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getComponent().items = [{id: 1}, {id: 2}];
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expect(() => fixture.detectChanges())
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.toThrowError(/trackBy must be a function, but received null/);
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it('should track by identity when trackBy is to `null` or `undefined`', async(() => {
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// TODO(vicb): expect no warning message when we have a proper log service
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const template =
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`<template ngFor let-item [ngForOf]="items" [ngForTrackBy]="value">{{ item }}</template>`;
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fixture = createTestComponent(template);
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fixture.componentInstance.items = ['a', 'b', 'c'];
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fixture.componentInstance.value = null;
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detectChangesAndExpectText('abc');
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fixture.componentInstance.value = undefined;
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detectChangesAndExpectText('abc');
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}));
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it('should set the context to the component instance', async(() => {
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@ -343,6 +354,7 @@ export function main() {
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getComponent().items = [{'id': 'a', 'color': 'red'}];
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detectChangesAndExpectText('red');
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}));
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it('should move items around and keep them updated ', async(() => {
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const template =
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`<div><template ngFor let-item [ngForOf]="items" [ngForTrackBy]="trackById">{{item['color']}}</template></div>`;
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@ -378,6 +390,7 @@ class Foo {
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@Component({selector: 'test-cmp', template: ''})
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class TestComponent {
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@ContentChild(TemplateRef) contentTpl: TemplateRef<Object>;
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value: any;
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items: any[] = [1, 2];
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trackById(index: number, item: any): string { return item['id']; }
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trackByIndex(index: number, item: any): number { return index; }
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@ -394,4 +407,4 @@ const TEMPLATE = '<div><span template="ngFor let item of items">{{item.toString(
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function createTestComponent(template: string = TEMPLATE): ComponentFixture<TestComponent> {
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return TestBed.overrideComponent(TestComponent, {set: {template: template}})
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.createComponent(TestComponent);
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}
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}
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