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Answer:59 using injectionToken and runInInjectionContext #1269

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34 changes: 28 additions & 6 deletions apps/angular/59-content-projection-defer/src/app/page-2.ts
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,13 @@ import { httpResource } from '@angular/common/http';
import {
ChangeDetectionStrategy,
Component,
computed,
EnvironmentInjector,
inject,
InjectionToken,
ResourceStatus,
runInInjectionContext,
viewChild,
} from '@angular/core';
import { ExpandableCard } from './expandable-card';

Expand All @@ -13,19 +19,25 @@ interface Post {
userId: number;
}

const PostResources = new InjectionToken('Fetch Post resources', {
providedIn: 'root',
factory: () =>
httpResource<Post[]>('https://jsonplaceholder.typicode.com/posts'),
});

@Component({
selector: 'app-page-2',
template: `
page2
<app-expandable-card>
<div title>Load Post</div>
<div>
@if (postRessource.isLoading()) {
@if (postResource()?.isLoading()) {
Loading...
} @else if (postRessource.status() === ResourceStatus.Error) {
} @else if (postResource()?.status() === ResourceStatus.Error) {
Error...
} @else {
@for (post of postRessource.value(); track post.id) {
@for (post of postResource()?.value(); track post.id) {
<div>{{ post.title }}</div>
}
}
Expand All @@ -36,8 +48,18 @@ interface Post {
imports: [ExpandableCard],
})
export class Page2 {
public postRessource = httpResource<Post[]>(
'https://jsonplaceholder.typicode.com/posts',
);
private readonly environmentInjector = inject(EnvironmentInjector);

private expandableCard = viewChild(ExpandableCard);

protected postResource = computed(() => {
if (this.expandableCard()?.isExpanded()) {
return runInInjectionContext(this.environmentInjector, () => {
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you should not use runInInjectionContext, this should always be avoided.

return inject(PostResources);
});
}
return undefined;
});

protected readonly ResourceStatus = ResourceStatus;
}