"use strict";
var exhaust_1 = require('../operators/exhaust');
/**
 * Converts a higher-order Observable into a first-order Observable by dropping
 * inner Observables while the previous inner Observable has not yet completed.
 *
 * Flattens an Observable-of-Observables by dropping the
 * next inner Observables while the current inner is still executing.
 *
 *  *
 * `exhaust` subscribes to an Observable that emits Observables, also known as a
 * higher-order Observable. Each time it observes one of these emitted inner
 * Observables, the output Observable begins emitting the items emitted by that
 * inner Observable. So far, it behaves like {@link mergeAll}. However,
 * `exhaust` ignores every new inner Observable if the previous Observable has
 * not yet completed. Once that one completes, it will accept and flatten the
 * next inner Observable and repeat this process.
 *
 * @example
 *
 * `exhaust` subscribes to an Observable that emits Observables, also known as a
 * higher-order Observable. Each time it observes one of these emitted inner
 * Observables, the output Observable begins emitting the items emitted by that
 * inner Observable. So far, it behaves like {@link mergeAll}. However,
 * `exhaust` ignores every new inner Observable if the previous Observable has
 * not yet completed. Once that one completes, it will accept and flatten the
 * next inner Observable and repeat this process.
 *
 * @example