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

#queue_update, #remove_anchors, #section, #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)
  # puts "New EACH Binding"

  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

  @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

#item_added(position) ⇒ Object 



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# File 'lib/volt/page/bindings/each_binding.rb', line 58

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

  if position >= @templates.size
    # Setup new bindings in the spot we want to insert the item
    section.insert_anchor_before_end(binding_name)
  else
    # Insert the item before an existing item
    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 48

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 change event comes through, its most likely upstream, so the whole array might have changed. In this case, just reload the whole thing TODO: Track to make sure the changed event isn’t being called too often (it is currently)



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# File 'lib/volt/page/bindings/each_binding.rb', line 28

def reload
  # ObjectTracker.enable_cache
  # Remove all of the current templates
  if @templates
    @templates.each do |template|
      template.remove_anchors

      # TODO: Make sure this is being removed since we already removed the anchors
      template.remove
    end
  end

  @templates = []

  # Run update again to rebuild
  update

  # ObjectTracker.disable_cache
end

#remove ⇒ Object

When this each_binding is removed, cleanup.



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# File 'lib/volt/page/bindings/each_binding.rb', line 110

def remove
  # puts "Remove Each"
  @added_listener.remove
  @added_listener = nil

  @changed_listener.remove
  @changed_listener = nil

  @removed_listener.remove
  @removed_listener = nil

  @templates.each(&:remove)
  @templates = nil

  super
end

#update(item = nil) ⇒ Object 



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# File 'lib/volt/page/bindings/each_binding.rb', line 94

def update(item=nil)
  if item
    values = [item]
  else
    values = @value.cur
    return if values.is_a?(Model) || values.is_a?(Exception)
    values = values.attributes
  end

  # TODO: Switch to #each?
  values.each_with_index do |value,index|
    item_added(index)
  end
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 85

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