Class: Volt::AttributeBinding

Inherits:
BaseBinding show all
Defined in:
lib/volt/page/bindings/attribute_binding.rb

Instance Attribute Summary

Attributes inherited from BaseBinding

#binding_name, #context, #target

Instance Method Summary collapse

Methods inherited from BaseBinding

#dom_section

Constructor Details

#initialize(page, target, context, binding_name, attribute_name, getter, setter) ⇒ AttributeBinding

Returns a new instance of AttributeBinding.



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 6

def initialize(page, target, context, binding_name, attribute_name, getter, setter)
  super(page, target, context, binding_name)

  @attribute_name = attribute_name
  @getter         = getter
  @setter         = setter

  setup
end

Instance Method Details

#changed(event = nil) ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 41

def changed(event = nil)
  case @attribute_name
    when 'value'
      current_value = element.value
    else
      current_value = element.is(':checked')
  end

  if @is_radio
    if current_value
      # if it is a radio button and its checked
      @context.instance_exec(@selected_value, &@setter)
    end
  else
    @context.instance_exec(current_value, &@setter)
  end
end

#element ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 59

def element
  Element.find('#' + binding_name)
end

#remove ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 115

def remove
  # Unbind events, leave the element there since attribute bindings
  # aren't responsible for it being there.
  case @attribute_name
    when 'value'
      element.off('input.attrbind', nil)
    when 'checked'
      element.off('change.attrbind', nil)
  end

  @string_template_renderer.remove if @string_template_renderer
  @string_template_renderer_computation.stop if @string_template_renderer_computation
  @computation.stop if @computation

  # Clear any references
  @target  = nil
  @context = nil
  @getter  = nil
end

#remove_anchors ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 135

def remove_anchors
  fail 'attribute bindings do not have anchors, can not remove them'
end

#setup ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 16

def setup
  # Listen for changes
  @computation = -> do
    begin
      update(@context.instance_eval(&@getter))
    rescue => e
      Volt.logger.error("AttributeBinding Error: #{e.inspect}")
      update('')
    end
  end.watch!

  @is_radio = element.is('[type=radio]')
  if @is_radio
    @selected_value = element.attr('value')
  end

  # Bind so when this value updates, we update
  case @attribute_name
    when 'value'
      element.on('input.attrbind') { changed }
    when 'checked'
      element.on('change.attrbind') { |event| changed(event) }
  end
end

#update(new_value) ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 63

def update(new_value)
  if @attribute_name == 'checked'
    update_checked(new_value)
    return
  end

  # Stop any previous reactive template computations
  @string_template_renderer_computation.stop if @string_template_renderer_computation
  @string_template_renderer.remove if @string_template_renderer

  if new_value.is_a?(StringTemplateRender)
    # We don't need to refetch the whole reactive template to
    # update, we can just depend on it and update directly.
    @string_template_renderer = new_value

    @string_template_renderer_computation = -> do
      self.value = @string_template_renderer.html
    end.watch!
  else
    if new_value.is_a?(NilMethodCall) || new_value.nil?
      new_value = ''
    end

    self.value = new_value
  end
end

#update_checked(value) ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 103

def update_checked(value)
  if value.is_a?(NilMethodCall) || value.nil?
    value = false
  end

  if @is_radio
    value = (@selected_value == value)
  end

  element.prop('checked', value)
end

#value=(val) ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 90

def value=(val)
  case @attribute_name
    when 'value'
      # TODO: only update if its not the same, this keeps it from moving the
      # cursor in text fields.
      if val != element.value
        element.value = val
      end
    else
      element[@attribute_name] = val
  end
end