Module: Puppeteer::EventCallbackable

Included in:
Browser, BrowserContext, CDPSession, Connection, FrameManager, NetworkManager, Page
Defined in:
lib/puppeteer/event_callbackable.rb

Defined Under Namespace

Classes: EventListeners

Instance Method Summary collapse

Instance Method Details

#add_event_listener(event_name, &block) ⇒ Object Also known as: on 



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# File 'lib/puppeteer/event_callbackable.rb', line 29

def add_event_listener(event_name, &block)
  @event_listeners ||= {}
  (@event_listeners[event_name] ||= EventListeners.new).add(&block)
end

#emit_event(event_name, *args, **kwargs) ⇒ Object 



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# File 'lib/puppeteer/event_callbackable.rb', line 62

def emit_event(event_name, *args, **kwargs)
  @event_callbackable_handlers ||= {}
  @event_listeners ||= {}

  if kwargs.empty?
    # In Ruby's specification (version < 2.7),
    # `method(:x).call(*args, **kwargs)` is equivalent to `x(*args, {})`
    # It often causes unexpected ArgumentError.
    #
    # ----------------
    # def greet
    #   puts 'Hello!'
    # end
    #
    # def call_me(*args, **kwargs)
    #   greet(*args, **kwargs) # => 'Hello!'
    #
    #   method(:greet).call(*args, **kwargs) # => `greet': wrong number of arguments (given 1, expected 0) (ArgumentError)
    # end
    #
    # call_me
    # ----------------
    #
    # This behavior is really annoying, and should be avoided, because we often want to set event handler as below:
    #
    # `on_event 'Some.Event.awesome', &method(:handle_awesome_event)`
    #
    # So Let's avoid it by checking kwargs.
    @event_callbackable_handlers[event_name]&.call(*args)
    @event_listeners[event_name]&.each do |proc|
      proc.call(*args)
    end
  else
    @event_callbackable_handlers[event_name]&.call(*args, **kwargs)
    @event_listeners[event_name]&.each do |proc|
      proc.call(*args, **kwargs)
    end
  end

  event_name
end

#observe_first(event_name, &block) ⇒ Object Also known as: once 



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# File 'lib/puppeteer/event_callbackable.rb', line 44

def observe_first(event_name, &block)
  listener_id = add_event_listener(event_name) do |*args, **kwargs|
    if kwargs.empty?
      block.call(*args)
    else
      block.call(*args, **kwargs)
    end
    remove_event_listener(listener_id)
  end
end

#on_event(event_name, &block) ⇒ Object 



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# File 'lib/puppeteer/event_callbackable.rb', line 57

def on_event(event_name, &block)
  @event_callbackable_handlers ||= {}
  @event_callbackable_handlers[event_name] = block
end

#remove_event_listener(*id_args) ⇒ Object 



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# File 'lib/puppeteer/event_callbackable.rb', line 36

def remove_event_listener(*id_args)
  (@event_listeners ||= {}).each do |event_name, listeners|
    id_args.each do |id|
      listeners.delete(id)
    end
  end
end