API Reference

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API Reference / @dasch-ng/rxjs-operators / pollUntil

Function: pollUntil()

pollUntil<T>(read, options?): Observable<NonNullable<T>>

Defined in: poll-until.ts:32

Reads a value repeatedly until it is ready, then emits it once and completes. The first read happens immediately, so an already available value is emitted synchronously.

Useful when something is initialised outside your control, e.g. an auth token or a third-party script global, and requests must wait for it.

Type Parameters

T

T

Parameters

read

() => T

options?

PollUntilOptions<T> = {}

Returns

Observable<NonNullable<T>>

Example

import { pollUntil } from '@dasch-ng/rxjs-operators';

pollUntil(() => auth.token, { timeout: 5000 })
  .pipe(switchMap((token) => http.get(url, { headers: { Authorization: `Bearer ${token}` } })))
  .subscribe();

pollUntil(() => window.someSdk, { interval: 250 }).subscribe((sdk) => sdk.init());