import {Operator} from '../Operator';
import {Observable} from '../Observable';
import {Subscriber} from '../Subscriber';
import {Subscription} from '../Subscription';
import {tryCatch} from '../util/tryCatch';
import {errorObject} from '../util/errorObject';
import {OuterSubscriber} from '../OuterSubscriber';
import {subscribeToResult} from '../util/subscribeToResult';
export function switchMapTo<T, R, R2>(observable: Observable<R>,
resultSelector?: (
outerValue: T,
innerValue: R,
outerIndex: number,
innerIndex: number) => R2): Observable<R2> {
return this.lift(new SwitchMapToOperator(observable, resultSelector));
}
class SwitchMapToOperator<T, R, R2> implements Operator<T, R> {
constructor(private observable: Observable<R>,
private resultSelector?: (outerValue: T, innerValue: R, outerIndex: number, innerIndex: number) => R2) {
}
call(subscriber: Subscriber<R>): Subscriber<T> {
return new SwitchMapToSubscriber(subscriber, this.observable, this.resultSelector);
}
}
class SwitchMapToSubscriber<T, R, R2> extends OuterSubscriber<T, R> {
private index: number = 0;
private innerSubscription: Subscription;
constructor(destination: Subscriber<R>,
private inner: Observable<R>,
private resultSelector?: (outerValue: T, innerValue: R, outerIndex: number, innerIndex: number) => R2) {
super(destination);
}
protected _next(value: any) {
const innerSubscription = this.innerSubscription;
if (innerSubscription) {
innerSubscription.unsubscribe();
}
this.add(this.innerSubscription = subscribeToResult(this, this.inner, value, this.index++));
}
protected _complete() {
const {innerSubscription} = this;
if (!innerSubscription || innerSubscription.isUnsubscribed) {
super._complete();
}
}
_unsubscribe() {
this.innerSubscription = null;
}
notifyComplete(innerSub: Subscription) {
this.remove(innerSub);
this.innerSubscription = null;
if (this.isStopped) {
super._complete();
}
}
notifyNext(outerValue: T, innerValue: R, outerIndex: number, innerIndex: number) {
const { resultSelector, destination } = this;
if (resultSelector) {
const result = tryCatch(resultSelector)(outerValue, innerValue, outerIndex, innerIndex);
if (result === errorObject) {
destination.error(errorObject.e);
} else {
destination.next(result);
}
} else {
destination.next(innerValue);
}
}
}
|