aretherecookies-mobile/js/streams/PlacesStream.js

// @flow
import { buildPlaceRecord } from '../records/PlaceRecord';
import { Map } from 'immutable';
import foodItems$ from './FoodItemsStream';
import { getPlaceDetails } from '../apis/PlaceDetailsApi';
import { memoize } from 'ramda';
import { Observable } from 'rxjs';
import typeof FoodItemRecord from '../records/FoodItemRecord';
import PlaceRecord, { type GooglePlaceObj } from '../records/PlaceRecord';
import { setById } from '../helpers/ImmutableHelpers';

/**
 * return a promise of a place details object
 * if already requested return existing promise
 * swallow exceptions so as not to break the stream
 */
const safeGetPlaceDetails = memoize((placeId: string): Promise<?GooglePlaceObj> => {
	return getPlaceDetails(placeId).catch(error => {
		console.log(error); // eslint-disable-line no-console
		return null;
	});
});

export default foodItems$
	.map((foodItems: Map<string, FoodItemRecord>): Array<string> => {
		return foodItems.map(foodItem => foodItem.placeId).toArray();
	})
	.mergeMap((placeIds: Array<string>): Observable<Array<Promise<?GooglePlaceObj>>> => {
		return Observable.forkJoin(placeIds.map(safeGetPlaceDetails));
	})
	.map((places: Array<GooglePlaceObj>): Map<string, PlaceRecord> => {
		return places.map(buildPlaceRecord).reduce(setById, new Map());
	});