observer.coffee

Meteor.publish 'order_book', (pairId) ->
  return unless pairId
  selector =
    pairId: pairId
    complete: false
    cancelled: false

    bids = {}
    asks = {}
    obs = Orders.find(selector).observe
      changed: (oldOrder, newOrder) =>
        console.log oldOrder, newOrder

order.coffee

class @Order
  doWithLock: (func) ->
    try
      Orders.update(@_id, $set: {locked: true})
      func()
    finally
      Orders.update(@_id, $set: {locked: false})
  
  cancel: ->
    @doWithLock =>
      @unlockFunds()
      Orders.update(@_id, $set: {cancelled: true})