Module: Browser::DelegateNative

Included in:
Element
Defined in:
lib/browser/delegate_native.rb

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(message, *args, &block) ⇒ Object

Fall back to native properties. If the message sent to this element is not recognized, it checks to see if it is a property of the native element. It also checks for variations of the message name, such as:

:supported? => [:supported, :isSupported]

If a property with the specified message name is found and it is a function, that function is invoked with ‘args`. Otherwise, the property is returned as is.



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# File 'lib/browser/delegate_native.rb', line 18

def method_missing message, *args, &block
  property_name = property_for_message(message)
  property = `#@native[#{property_name}]`

  # translate setting a property
  if message.end_with? '='
    return `#@native[#{property_name}] = args[0]`
  end

  # If the native element doesn't have this property, bubble it up
  super unless `#{property_name} in #@native`

  if `property === false`
    return false
  elsif `typeof(property) === 'number' && isNaN(property)`
    return nil
  else
    property = `property == null ? nil : property`
  end

  # If it's a method, call it. Otherwise, return it.
  if `typeof(property) === 'function'`
    `property.apply(#@native, args)`
  else
    property
  end
end

Instance Method Details

#initialize(native) ⇒ Object

Provides a default initializer. This should be overridden in all but the simplest cases.



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# File 'lib/browser/delegate_native.rb', line 5

def initialize native
  @native = native
end

#property_for_message(message) ⇒ Object 



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# File 'lib/browser/delegate_native.rb', line 53

def property_for_message message
  camel_cased_message = message
    .gsub(/_\w/) { |match| `match[1]`.upcase }
    .sub(/=$/, '')

  # translate `supported?` to `supported` or `isSupported`
  if message.end_with? '?'
    camel_cased_message = camel_cased_message.chop
    property_type = `typeof(#@native[camel_cased_message])`
    if property_type == 'undefined'
      camel_cased_message = "is#{camel_cased_message[0].upcase}#{camel_cased_message[1..-1]}"
    end
  end

  camel_cased_message
end

#respond_to_missing?(message, include_all) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/browser/delegate_native.rb', line 46

def respond_to_missing? message, include_all
  return true if message.end_with? '='
  return true if property_for_message(message)

  false
end