hunk.code_window:     "removeComments": true,
       "preserveConstEnums": true,
       "sourceMap": true,
       "strictFunctionTypes": true,
       "noImplicitAny": true,
       "noImplicitReturns": true,
  
hunk.labels: keep keep keep replace replace keep
hunk.after_edit:     "strict": true,
       "strictNullChecks": false,
       "strictPropertyInitialization": false,
  
hunk.file_path: tsconfig.json
hunk.type: replace
file: import { Operator } from '../Operator';
  import { Observable } from '../Observable';
  import { Subscriber } from '../Subscriber';
  import { Subscription } from '../Subscription';
  import { OuterSubscriber } from '../OuterSubscriber';
  import { InnerSubscriber } from '../InnerSubscriber';
  import { subscribeToResult } from '../util/subscribeToResult';
  import { ObservableInput, OperatorFunction, ObservedValueOf } from '../types';
  import { map } from './map';
  import { from } from '../observable/from';
  
  /* tslint:disable:max-line-length */
  export function exhaustMap<T, O extends ObservableInput<any>>(project: (value: T, index: number) => O): OperatorFunction<T, ObservedValueOf<O>>;
  /** @deprecated resultSelector is no longer supported. Use inner map instead. */
  export function exhaustMap<T, O extends ObservableInput<any>>(project: (value: T, index: number) => O, resultSelector: undefined): OperatorFunction<T, ObservedValueOf<O>>;
  /** @deprecated resultSelector is no longer supported. Use inner map instead. */
  export function exhaustMap<T, I, R>(project: (value: T, index: number) => ObservableInput<I>, resultSelector: (outerValue: T, innerValue: I, outerIndex: number, innerIndex: number) => R): OperatorFunction<T, R>;
  /* tslint:enable:max-line-length */
  
  /**
   * Projects each source value to an Observable which is merged in the output
   * Observable only if the previous projected Observable has completed.
   *
   * <span class="informal">Maps each value to an Observable, then flattens all of
   * these inner Observables using {@link exhaust}.</span>
   *
   * ![](exhaustMap.png)
   *
   * Returns an Observable that emits items based on applying a function that you
   * supply to each item emitted by the source Observable, where that function
   * returns an (so-called "inner") Observable. When it projects a source value to
   * an Observable, the output Observable begins emitting the items emitted by
   * that projected Observable. However, `exhaustMap` ignores every new projected
   * Observable if the previous projected Observable has not yet completed. Once
   * that one completes, it will accept and flatten the next projected Observable
   * and repeat this process.
   *
   * ## Example
   * Run a finite timer for each click, only if there is no currently active timer
   * ```ts
   * import { fromEvent, interval } from 'rxjs';
   * import { exhaustMap, take } from 'rxjs/operators';
   *
   * const clicks = fromEvent(document, 'click');
   * const result = clicks.pipe(
   *   exhaustMap(ev => interval(1000).pipe(take(5)))
   * );
   * result.subscribe(x => console.log(x));
   * ```
   *
   * @see {@link concatMap}
   * @see {@link exhaust}
   * @see {@link mergeMap}
   * @see {@link switchMap}
   *
   * @param {function(value: T, ?index: number): ObservableInput} project A function
   * that, when applied to an item emitted by the source Observable, returns an
   * Observable.
   * @return {Observable} An Observable containing projected Observables
   * of each item of the source, ignoring projected Observables that start before
   * their preceding Observable has completed.
   * @method exhaustMap
   * @owner Observable
   */
  export function exhaustMap<T, R, O extends ObservableInput<any>>(
    project: (value: T, index: number) => O,
    resultSelector?: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R,
  ): OperatorFunction<T, ObservedValueOf<O>|R> {
    if (resultSelector) {
      // DEPRECATED PATH
      return (source: Observable<T>) => source.pipe(
        exhaustMap((a, i) => from(project(a, i)).pipe(
          map((b: any, ii: any) => resultSelector(a, b, i, ii)),
        )),
      );
    }
    return (source: Observable<T>) =>
      source.lift(new ExhaustMapOperator(project));
  }
  
  class ExhaustMapOperator<T, R> implements Operator<T, R> {
    constructor(private project: (value: T, index: number) => ObservableInput<R>) {
    }
  
    call(subscriber: Subscriber<R>, source: any): any {
      return source.subscribe(new ExhaustMapSubscriber(subscriber, this.project));
    }
  }
  
  /**
   * We need this JSDoc comment for affecting ESDoc.
   * @ignore
   * @extends {Ignored}
   */
  class ExhaustMapSubscriber<T, R> extends OuterSubscriber<T, R> {
    private hasSubscription = false;
    private hasCompleted = false;
    private index = 0;
  
    constructor(destination: Subscriber<R>,
                private project: (value: T, index: number) => ObservableInput<R>) {
      super(destination);
    }
  
    protected _next(value: T): void {
      if (!this.hasSubscription) {
        this.tryNext(value);
      }
    }
  
    private tryNext(value: T): void {
      let result: ObservableInput<R>;
      const index = this.index++;
      try {
        result = this.project(value, index);
      } catch (err) {
        this.destination.error(err);
        return;
      }
      this.hasSubscription = true;
      this._innerSub(result, value, index);
    }
  
    private _innerSub(result: ObservableInput<R>, value: T, index: number): void {
      const innerSubscriber = new InnerSubscriber(this, value, index);
      const destination = this.destination as Subscription;
      destination.add(innerSubscriber);
      const innerSubscription = subscribeToResult<T, R>(this, result, undefined, undefined, innerSubscriber);
      // The returned subscription will usually be the subscriber that was
      // passed. However, interop subscribers will be wrapped and for
      // unsubscriptions to chain correctly, the wrapper needs to be added, too.
      if (innerSubscription !== innerSubscriber) {
        destination.add(innerSubscription);
      }
    }
  
    protected _complete(): void {
      this.hasCompleted = true;
      if (!this.hasSubscription) {
        this.destination.complete();
      }
      this.unsubscribe();
    }
  
    notifyNext(outerValue: T, innerValue: R,
               outerIndex: number, innerIndex: number,
               innerSub: InnerSubscriber<T, R>): void {
      this.destination.next(innerValue);
    }
  
    notifyError(err: any): void {
      this.destination.error(err);
    }
  
    notifyComplete(innerSub: Subscription): void {
      const destination = this.destination as Subscription;
      destination.remove(innerSub);
  
      this.hasSubscription = false;
      if (this.hasCompleted) {
        this.destination.complete();
      }
    }
  }
  