trc-client-core/src/course/CourseReducer.js

The core of the TRC Client

import {
    COURSE_ERROR,
    COURSE_FETCH,
    COURSE_RECEIVE,
    COURSE_SIMILAR_ERROR,
    COURSE_SIMILAR_FETCH,
    COURSE_SIMILAR_RECEIVE,
    COURSE_LIST_FETCH,
    COURSE_LIST_RECEIVE,
    COURSE_LIST_ERROR
} from 'trc-client-core/src/constants/ActionTypes';

import {Map, OrderedMap, fromJS} from 'immutable';

const initialState = Map({
    fetching: false,
    collection: OrderedMap({})
});

function reduceToOrderedMap(payload) {
    return fromJS(payload)
        .reduce((reduction, item) => reduction.set(item.get('courseCode'), item), OrderedMap());
}

export default function course(state = initialState, action) {
    switch (action.type) {
        case COURSE_FETCH:
        case COURSE_LIST_FETCH:
        case COURSE_SIMILAR_FETCH:
            return state
                .set('fetching', true);        

        case COURSE_ERROR:
        case COURSE_LIST_ERROR:
        case COURSE_SIMILAR_ERROR:
            return state
                .set('fetching', false)
                .set('error', action.payload);

        case COURSE_RECEIVE:
            return state
                .setIn(['collection', action.payload.courseCode], fromJS(action.payload))
                .set('fetching', false);

        case COURSE_LIST_RECEIVE:
        case COURSE_SIMILAR_RECEIVE:
            return state
                .mergeDeepIn(['collection'], reduceToOrderedMap(action.payload));


        default: 
            return state;
    }
}