switchMap.js 1.15 KB
import { innerFrom } from '../observable/innerFrom';
import { operate } from '../util/lift';
import { createOperatorSubscriber } from './OperatorSubscriber';
export function switchMap(project, resultSelector) {
    return operate((source, subscriber) => {
        let innerSubscriber = null;
        let index = 0;
        let isComplete = false;
        const checkComplete = () => isComplete && !innerSubscriber && subscriber.complete();
        source.subscribe(createOperatorSubscriber(subscriber, (value) => {
            innerSubscriber === null || innerSubscriber === void 0 ? void 0 : innerSubscriber.unsubscribe();
            let innerIndex = 0;
            const outerIndex = index++;
            innerFrom(project(value, outerIndex)).subscribe((innerSubscriber = createOperatorSubscriber(subscriber, (innerValue) => subscriber.next(resultSelector ? resultSelector(value, innerValue, outerIndex, innerIndex++) : innerValue), () => {
                innerSubscriber = null;
                checkComplete();
            })));
        }, () => {
            isComplete = true;
            checkComplete();
        }));
    });
}
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