reducer.js

function (state = {}, action) {
    switch (action.type) {
        case 'VIEW_ORDERS': 
            return {
                ...state,
                pageType: 'orders',
                orderId: null
            };
        case 'VIEW_ORDER':
            return {
                ...state,
                pageType: 'order',
                orderId: action.orderId
            };
        case 'VIEW_RECEIPT':
            return {
                ...state,
                pageType: 'receipt',
                orderId: action.orderId
            };
        }
    return state;
}