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, #volt_app

Instance Method Summary collapse

Methods inherited from BaseBinding

#dom_section, #getter_fail, #page

Constructor Details

#initialize(volt_app, 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(volt_app, target, context, binding_name, attribute_name, getter, setter)
  super(volt_app, 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 52

def changed(event = nil)
  case @attribute_name
    when 'value'
      current_value = `#{element}.val() || ''`
    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 70

def element
  @element ||= `$('#' + #{binding_name})`
end

#remove ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 127

def remove
  # Unbind events, leave the element there since attribute bindings
  # aren't responsible for it being there.
  case @attribute_name
    when 'value'
      if @is_select
        `#{element}.off('change.attrbind')`
      elsif @is_hidden
        `#{element}.unwatch('value')`
      else
        `#{element}.off('input.attrbind', #{nil})`
      end
    when 'checked'
      `#{element}.off('change.attrbind', #{nil})`
  end

  if @computation
    @computation.stop
    @computation = nil
  end

  @string_template_renderer.remove if @string_template_renderer
  @string_template_renderer_computation.stop if @string_template_renderer_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 157

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 = lambda do
    begin
      @context.instance_eval(&@getter)
    rescue => e
      getter_fail(e)
      ''
    end
  end.watch_and_resolve!(
    method(:update),
    method(:getter_fail)
  )

  @is_select = `#{element}.is('select')`
  @is_hidden = `#{element}.is('[type=hidden]')`
  @is_radio = `#{element}.is('[type=radio]')`
  @selected_value = `#{element}.attr('value') || ''` if @is_radio

  # Bind so when this value updates, we update
  case @attribute_name
    when 'value'
      changed_event = Proc.new { changed }
      if @is_select
        `#{element}.on('change.attrbind', #{changed_event})`
      elsif @is_hidden
        `#{element}.watch('value', #{changed_event})`
      else
        `#{element}.on('input.attrbind', #{changed_event})`
      end
    when 'checked'
      changed_event = proc { |event| changed(event) }
      `#{element}.on('change.attrbind', #{changed_event})`
  end
end

#update(new_value) ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 74

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?(StringTemplateRenderer)
    # 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 = lambda do
      self.value = @string_template_renderer.html
    end.watch!
  else
    new_value = '' if new_value.is_a?(NilMethodCall) || new_value.nil?

    self.value = new_value
  end
end

#update_checked(value) ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 119

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

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

  `#{element}.prop('checked', #{value})`
end

#value=(val) ⇒ Object 



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# File 'lib/volt/page/bindings/attribute_binding.rb', line 99

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.
      `#{element}.val(#{val})` if val != `(#{element}.val() || '')`
    when 'disabled'
      # Disabled is handled specially, you can either return a boolean:
      # (true being disabled, false not disabled), or you can optionally
      # include the "disabled" string. (or any string)
      if val != false && val.present?
        `#{element}.attr('disabled', 'disabled')`
      else
        `#{element}.removeAttr('disabled')`
      end
    else
      `#{element}.attr(#{@attribute_name}, #{val})`
  end
end