meta-reducers.functions.ts

// This function takes a reducer and a name, and returns a reducer that essentially filters on the name.
// Useful for when you have multiple reducers of the same form.
export function createNamedWrapperReducer<T>(
	reducerFunction: ( ( state, action ) => T ), reducerName: string ): ( ( state, action ) => T ) {
	return ( state, action ) => {
		const { name } = action;
		const isInitializationCall = state === undefined;
		if ( name !== reducerName && !isInitializationCall ) {
			return state;
		}

		return reducerFunction( state, action );
	}
}

subscription-statuses.reducer.ts

import { addToList } from '@geek/store/shared/type-sorted-list.functions';
import { TypeSortedList } from '@geek/store/shared/type-sorted-list.interface';

import { createNamedWrapperReducer } from '@geek/store/meta/meta-reducers.functions';
import { SubscriptionStatus } from '@geek/store/subscriptions/subscription-status.model';
import { SubscriptionType } from '@geek/store/subscriptions/subscription-type.type';
import * as subscriptionsActions from '@geek/store/subscriptions/subscriptions.actions';
import * as _ from 'lodash';

export const defaultStatus: SubscriptionStatus = {
	exists: false,
	loading: false,
	firstLoad: false,
};

export interface State {
	statuses: TypeSortedList<SubscriptionStatus>;
}

const initialState: State = {
	statuses: {},
};

export function reducer( state = initialState, action: subscriptionsActions.Actions ): State {
	let type, id;
	let statuses;
	let status;

	switch ( action.type ) {
		case subscriptionsActions.LOAD_STATUS_BY_ITEM:
			({ type, id } = action.payload.parent);
			status = _.get( state.statuses, [type, id], defaultStatus );
			statuses = addToList( state.statuses, type, id, {...status, loading: true } );
			return { statuses };

		case subscriptionsActions.LOAD_STATUS_BY_ITEM_SUCCESS:
			({ type, id } = action.payload.parent);
			statuses = addToList(
				state.statuses, type, id, { exists: action.payload.results, loading: false, firstLoad: true } );
			return { statuses };

		case subscriptionsActions.ADD:
			({ type, id } = action.payload.parent);
			statuses = addToList(
				state.statuses, type, id, { exists: true, loading: true, firstLoad: false } );
			return { statuses };

		case subscriptionsActions.REMOVE:
			({ type, id } = action.payload.parent);
			statuses = addToList(
				state.statuses, type, id, { exists: false, loading: true, firstLoad: false } );
			return { statuses };

		case subscriptionsActions.ADD_SUCCESS:
		case subscriptionsActions.REMOVE_SUCCESS:
			({ type, id } = action.payload.parent);
			status = _.get( state.statuses, [type, id], defaultStatus );
			statuses = addToList(
				state.statuses, type, id, {...status, loading: false, firstLoad: true } );
			return { statuses };

		default:
			return state;
	}
}

export function createSubscriptionStatusesReducer( subscriptionType: SubscriptionType ) {
	return createNamedWrapperReducer( reducer, subscriptionType );
}

export const getSubscriptionStatuses = ( state: State ) => state.statuses;