actors.ts

const addItem = defineSignal('addItem')
const checkout = defineSignal('checkout')

function cart(userId) {
  const items = []
  
  setHandler(addItem, (item) => items.push(item))
  
  setHandler(checkout, () => {
    const userInfo = await getUser(userId) // activity that gets a handle to the User workflow with Workflow Id = userId and does a 'getUserInfo' Query
    const amount = calculateTotal(items) // helper function, not an activity
    const paymentId = await chargeUser(userInfo, amount)
    try {
      const trackingNumber = await ship(items, userInfo)
    } catch (e) {
      await refundUser(paymentId)
      throw e
    }
    const user = getExternalWorkflowHandle(userId)
    user.signal(addOrder, { items, paymentId, trackingNumber })
  })

  await CancellationScope.current().cancelRequested
}


const setAddress = defineSignal('setAddress')
const setPaymentMethod = defineSignal('setPaymentMethod')
const addOrder = defineSignal('addOrder')
const getUserInfo = defineQuery('getUserInfo')

function user(userInfo) {
  const orders = []

  setHandler(setAddress, (address) => {
    userInfo.address = address
    await notifyUser('Address updated')
  })

  setHandler(setPaymentMethod, (paymentMethodId) => {
    userInfo.paymentMethodId = paymentMethodId
    await notifyUser('Payment method updated')
  })
  
  setHandler(addOrder, (order) => {
    orders.push(order)
    await notifyUser('Order complete!')
  })

  setHandler(getUserInfo, () => ({ ...userInfo, orders }))

  await CancellationScope.current().cancelRequested
}