fnuff.js

const customerRevenueNode = (store) => {

  return createNode({

    accessMemory: {
      'orderCancelled': (order) =>
        _store.GetByOrderId(order.orderId)
          .then((snapshot) => {
            snapshot,
            save: (nextState) => _store.save(nextState)
          }),
      'orderPlaced': (order) =>
        _store.GetByCustomerId(order.orderId)
          .then((snapshot) => {
            snapshot,
            save: (nextState) => _store.save(nextState)
          }),
      'orderDelivered': (order) =>
        _store.GetByOrderId(order.orderId)
          .then((snapshot) => {
            snapshot,
            save: (nextState) => _store.save(nextState)
          })
    },

    transform: {
      'orderCancelled': (order, state) => R.merge({
        { customerId: order.customerId },
        {
          pendingOrderAmounts: R.reject(
            (state.pendingOrderAmounts || []),
            amount => amount.id === order.id
          )
        }
      ),
      'orderPlaced': (order, state) => R.merge(
        { customerId: order.customerId },
        {
          pendingOrderAmounts: R.reject(
            (state.pendingOrderAmounts || []),
            [{ id: order.id, amount: order.amount }]
          )
        }
      ),
      'orderDelivered': (order, state) => R.merge({
        { customerId: order.customerId },
        {
          pendingOrderAmounts: R.reject(
            (state.pendingOrderAmounts || []),
            [{ id: order.id, amount: order.amount }]
          ),
          aggregatedRevenue:
            state.aggregatedRevenue +
              R.find(state.pendingOrderAmounts,
                amount => amount.id === order.id).amount
        }
      })
    }

  })