Angular 16: solution with Change Detection in Custom Pipes with Async Data
I'm having issues with change detection in my Angular 16 application when using custom pipes with asynchronous data sources. I created a custom pipe that formats a date string based on the user's locale, but it seems to not update when the data changes asynchronously. Here’s the relevant code for the custom pipe: ```typescript import { Pipe, PipeTransform } from '@angular/core'; import { formatDate } from '@angular/common'; @Pipe({ name: 'localizedDate', pure: false }) export class LocalizedDatePipe implements PipeTransform { transform(value: string, locale: string): string { return formatDate(value, 'medium', locale); } } ``` I used this pipe in my template like this: ```html <div *ngFor="let item of items"> <p>{{ item.date | localizedDate: userLocale }}</p> </div> ``` The `items` array is populated from an asynchronous service call that gets the data every 5 seconds. When the data updates, I see the new dates being logged in the console, but the displayed dates do not change. I made sure to mark the pipe as `pure: false`, thinking that it should trigger change detection when the data updates. I've tried forcing change detection by injecting `ChangeDetectorRef` into my component and calling `markForCheck()` after the service call, but it still does not work as expected. Here’s how I’m calling the service: ```typescript ngOnInit() { this.updateData(); setInterval(() => this.updateData(), 5000); } updateData() { this.dataService.getItems().subscribe(data => { this.items = data; this.cd.markForCheck(); }); } ``` I also checked if the `userLocale` is updated correctly, which it is. However, I still need to figure out why the displayed date isn't changing. Anyone encountered a similar scenario or can suggest a solution? Am I missing something about how change detection works with custom pipes in Angular?