aretherecookies-mobile/js/streams/FavesStream.js

//@flow
import { BehaviorSubject } from 'rxjs';
import { Record, List, get } from 'immutable';
import filter$ from './FilterStream';
import foodItems$ from './FoodItemsStream';
import { test } from 'ramda';

export type Fave = {
	food_item_id: string,
	date: number,
};
export type Faves = List<Record>;

const observable: BehaviorSubject<Faves> = new BehaviorSubject(null);

export function emit(fave: ?Faves) {
	observable.next(fave);
}

export function emitOne(fave: ?Fave) {
	observable.first().subscribe(currentFaves => observable.next(currentFaves.push(fave)));
}

export default observable
	.combineLatest(foodItems$)
	.map(([faves, foodItems]) => {
		return faves && faves.map(fave => get(foodItems, get(fave, 'food_item_id')));
	})
	.combineLatest(filter$)
	.map(([faveFoodItems, filter]) => {
		const filterTest = filter.search && test(new RegExp(filter.search, 'i'));
		return (
			faveFoodItems &&
			faveFoodItems.filter(faveFoodItem => {
				if (!faveFoodItem) {
					return false;
				}
				return !filterTest || filterTest(faveFoodItem.name);
			})
		);
	});