RxJS & HttpClient Handlers

In addition to Promises, ngx-task accepts RxJS Observable streams directly inside handler functions.

import { HttpClient } from '@angular/common/http';
import { inject } from '@angular/core';
import { createTask } from 'ngx-task';

export class UserListComponent {
  private http = inject(HttpClient);

  readonly loadUsers = createTask((role: string) => {
    return this.http.get<User[]>(`/api/users?role=${role}`);
  });
}

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Automatic Subscription Cleanup

When a task returning an Observable is cancelled, superseded, or destroyed:

1. ngx-task calls .unsubscribe() on the active RxJS Subscription.
2. Angular’s HttpClient listens to unsubscription and automatically cancels the underlying XMLHttpRequest / Fetch request.

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observableResult Resolution Policies

Because Observables can emit multiple values over time, ngx-task allows configuring how emissions update the task.result signal:

Policy	Behavior
'latest' (Default)	Updates task.result signal on every emission, storing the latest value.
'first'	Captures the first emission as the result and ignores subsequent emissions.
'last'	Waits for Observable to complete and captures the final emission.
'forbid-multiple'	Throws an error if the Observable emits more than once.

const livePriceTask = createTask(
  (symbol: string) => priceStreamService.watchSymbol(symbol),
  {
    observableResult: 'latest', // Signal updates in real-time as stream emits
  },
);