import { Observable } from '../Observable';
/**
* Converts a higher-order Observable into a first-order Observable by waiting
* for the outer Observable to complete, then applying {@link combineLatest}.
*
* Flattens an Observable-of-Observables by applying
* {@link combineLatest} when the Observable-of-Observables completes.
*
*
*
* Takes an Observable of Observables, and collects all Observables from it.
* Once the outer Observable completes, it subscribes to all collected
* Observables and combines their values using the {@link combineLatest}
* strategy, such that:
* - Every time an inner Observable emits, the output Observable emits.
* - When the returned observable emits, it emits all of the latest values by:
* - If a `project` function is provided, it is called with each recent value
* from each inner Observable in whatever order they arrived, and the result
* of the `project` function is what is emitted by the output Observable.
* - If there is no `project` function, an array of all of the most recent
* values is emitted by the output Observable.
*
* @example