extension/includes/unload.coffee

   1 unload = do ->
   2   # Initialize the array of unloaders on the first usage
   3   unloaders = []
   4
   5   return (callback, container) ->
   6
   7     # Calling with no arguments runs all the unloader callbacks
   8     if !callback
   9       unloader() for unloader in unloaders
  10       unloaders.length = 0
  11
  12     # The callback is bound to the lifetime of the container if we have one
  13     else if container
  14       # Remove the unloader when the container unloads
  15       container.addEventListener('unload', removeUnloader, false)
  16
  17       # Wrap the callback to additionally remove the unload listener
  18       origCallback = callback
  19       callback = ->
  20         container.removeEventListener('unload', removeUnloader, false)
  21         origCallback()
  22
  23     # Wrap the callback in a function that ignores failures
  24     unloader = -> try callback()
  25     unloaders.push(unloader)
  26
  27     # Provide a way to remove the unloader
  28     removeUnloader = ->
  29       index = unloaders.indexOf(unloader)
  30       if index > -1
  31         unloaders.splice(index, 1)
  32
  33     return removeUnloader