subscribeOverlayPositionChange() {
        return this.positionStrategy.positionChanges
            .pipe(map((/**
         * @param {?} position
         * @return {?}
         */
        (position) => position.connectionPair.originY)), distinct())
            .subscribe((/**
         * @param {?} position
         * @return {?}
         */
        (position) => {
            this.nzAutocomplete.dropDownPosition = position;
        }));
    }
/**
     * Subscription overlay position changes and reset dropdown position
     * @private
     * @return {?}
     */
Subscription overlay position changes and reset dropdown position
@private
@return {?}
Subscription overlay position changes and reset dropdown position @private @return { ? }
subscribeOverlayPositionChange() {
        return this.positionStrategy.positionChanges
            .pipe(map((
        (position) => position.connectionPair.originY)), distinct())
            .subscribe((
        (position) => {
            this.nzAutocomplete.dropDownPosition = position;
        }));
    }
subscribeOverlayPositionChange ( ) { return this . positionStrategy . positionChanges . pipe ( map ( ( ( position ) => position . connectionPair . originY ) ) , distinct ( ) ) . subscribe ( ( ( position ) => { this . nzAutocomplete . dropDownPosition = position ; } ) ) ; }
Subscription overlay position changes and reset dropdown position
 @private
 @return {?}
Subscription overlay position changes and reset dropdown position @private @return { ? }
/**
         * @param {?} position
         * @return {?}
         */ /**
         * @param {?} position
         * @return {?}
         */