Module: Events

Included in:
ComponentNode, ReactiveManager, ReactiveTemplate, Temp1
Defined in:
lib/volt/reactive/events.rb

Instance Method Summary collapse

Instance Method Details

#event_chain ⇒ Object 



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# File 'lib/volt/reactive/events.rb', line 127

def event_chain
  @event_chain ||= EventChain.new(self)
end

#has_listeners? ⇒ Boolean

Returns:



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# File 'lib/volt/reactive/events.rb', line 135

def has_listeners?
  @has_listeners
end

#listeners ⇒ Object 



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# File 'lib/volt/reactive/events.rb', line 131

def listeners
  @listeners || {}
end

#on(event, scope_provider = nil, &block) ⇒ Object

Add a listener for an event



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# File 'lib/volt/reactive/events.rb', line 98

def on(event, scope_provider=nil, &block)

  event = event.to_sym

  @has_listeners = true

  new_listener = Listener.new(self, event, scope_provider, block)

  @listeners ||= {}
  @listeners[event] ||= []
  @listeners[event] << new_listener

  first_for_event = @listeners[event].size == 1
  first = first_for_event && @listeners.size == 1

  # When events get added, we need to notify event chains so they
  # can update and chain any new events.
  event_chain.add_event(event) if first_for_event

  # Let the included class know that an event was registered. (if it cares)
  if self.respond_to?(:event_added)
    # call event added passing the event, the scope, and a boolean if it
    # is the first time this event has been added.
    self.event_added(event, scope_provider, first, first_for_event)
  end

  return new_listener
end

#remove_listener(event, listener) ⇒ Object

Typically you would call .remove on the listener returned from the .on method. However, here you can also pass in the original proc to remove a listener



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# File 'lib/volt/reactive/events.rb', line 142

def remove_listener(event, listener)
  event = event.to_sym

  raise "Unable to delete #{event} from #{self.inspect}" unless @listeners && @listeners[event]

  @listeners[event].delete(listener)

  last_for_event = @listeners[event].size == 0

  if last_for_event
    # When events are removed, we need to notify any relevent chains so they
    # can remove any chained events.
    event_chain.remove_event(event)

    # No registered listeners now on this event
    @listeners.delete(event)
  end

  last = last_for_event && @listeners.size == 0

  # Let the class we're included on know that we removed a listener (if it cares)
  if self.respond_to?(:event_removed)
    # Pass in the event and a boolean indicating if it is the last event
    self.event_removed(event, last, last_for_event)
  end

  if last
    @has_listeners = nil
  end
end

#trigger!(event, filter = nil, *args) ⇒ Object 



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# File 'lib/volt/reactive/events.rb', line 173

def trigger!(event, filter=nil, *args)
  # puts "TRIGGER: #{event} on #{self.inspect}" if event == :added
  are_reactive = reactive?

  event = event.to_sym

  if @listeners && @listeners[event]
    # TODO: We have to dup here because one trigger might remove another
    @listeners[event].dup.each do |listener|
      # Call the event on each listener
      # If there is no listener, that means another event trigger removed it.
      # If there is no filter, call
      # if we aren't reactive, we should pass to all of our reactive listeners, since they
      # just proxy us.
      # If the filter exists, check it
      if (!filter || (!are_reactive && listener.scope_provider.reactive?) || filter.call(listener.scope))
        listener.call(filter, *args)
      end
    end
  end

  nil
end

#trigger_by_scope!(event, *args, &block) ⇒ Object

Takes a block, which passes in



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# File 'lib/volt/reactive/events.rb', line 198

def trigger_by_scope!(event, *args, &block)
  trigger!(event, block, *args)
end

#trigger_for_methods!(event, *method_names) ⇒ Object

Takes an event and a list of method names, and triggers the event for each listener coming off of those methods.



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# File 'lib/volt/reactive/events.rb', line 204

def trigger_for_methods!(event, *method_names)
  trigger_by_scope!(event, [], nil) do |scope|
    if scope
      method_name = scope.first

      method_names.include?(method_name)
    else
      false
    end
  end
end