Class: EachBinding

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

Instance Attribute Summary

Attributes inherited from BaseBinding

#binding_name, #context, #target

Instance Method Summary collapse

Methods inherited from BaseBinding

#dom_section, #queue_update, #remove_anchors, #value_from_getter

Constructor Details

#initialize(page, target, context, binding_name, getter, variable_name, template_name) ⇒ EachBinding

Returns a new instance of EachBinding.



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# File 'lib/volt/page/bindings/each_binding.rb', line 4

def initialize(page, target, context, binding_name, getter, variable_name, template_name)
  super(page, target, context, binding_name)

  @item_name = variable_name
  @template_name = template_name

  # Find the source for the content binding
  @value = value_from_getter(getter)

  @templates = []

  # Run the initial render
  # update
  reload

  @added_listener = @value.on('added') { |_, position, item| item_added(position) }
  @changed_listener = @value.on('changed') { reload }
  @removed_listener = @value.on('removed') { |_, position| item_removed(position) }
end

Instance Method Details

#current_values ⇒ Object 



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# File 'lib/volt/page/bindings/each_binding.rb', line 88

def current_values
  values = @value.cur

  return [] if values.is_a?(Model) || values.is_a?(Exception)
  values = values.attributes unless values.is_a?(ReactiveArray)

  return values
end

#item_added(position) ⇒ Object 



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# File 'lib/volt/page/bindings/each_binding.rb', line 52

def item_added(position)
  # ObjectTracker.enable_cache
  binding_name = @@binding_number
  @@binding_number += 1

  if position >= @templates.size
    # Setup new bindings in the spot we want to insert the item
    dom_section.insert_anchor_before_end(binding_name)
  else
    # Insert the item before an existing item
    dom_section.insert_anchor_before(binding_name, @templates[position].binding_name)
  end

  index = ReactiveValue.new(position)
  value = @value[index]

  item_context = SubContext.new({@item_name => value, :index => index, :parent => @value}, @context)

  item_template = TemplateRenderer.new(@page, @target, item_context, binding_name, @template_name)
  @templates.insert(position, item_template)

  # update_indexes_after(position)
end

#item_removed(position) ⇒ Object 



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# File 'lib/volt/page/bindings/each_binding.rb', line 42

def item_removed(position)
  position = position.cur
  @templates[position].remove_anchors
  @templates[position].remove
  @templates.delete_at(position)

  # Removed at the position, update context for every item after this position
  update_indexes_after(position)
end

#reload ⇒ Object

When a changed event happens, we update to the new size.



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# File 'lib/volt/page/bindings/each_binding.rb', line 25

def reload
  # Adjust to the new size
  values = current_values
  templates_size = @templates.size
  values_size = values.size

  if templates_size < values_size
    (templates_size).upto(values_size-1) do |index|
      item_added(index)
    end
  elsif templates_size > values_size
    (templates_size-1).downto(values_size) do |index|
      item_removed(index)
    end
  end
end

#remove ⇒ Object

When this each_binding is removed, cleanup.



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

def remove
  @added_listener.remove
  @added_listener = nil

  @changed_listener.remove
  @changed_listener = nil

  @removed_listener.remove
  @removed_listener = nil

  if @templates
    @templates.compact.each(&:remove)
    @templates = nil
  end

  super
end

#update_indexes_after(start_index) ⇒ Object

When items are added or removed in the middle of the list, we need to update each templates index value.



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# File 'lib/volt/page/bindings/each_binding.rb', line 78

def update_indexes_after(start_index)
  size = @templates.size
  if size > 0
    puts @templates.inspect
    start_index.upto(size-1) do |index|
      @templates[index].context.locals[:index].cur = index
    end
  end
end