Class: Dommy::Attr

Inherits:
Object
  • Object
show all
Defined in:
lib/dommy/attr.rb

Overview

‘Attr` — wraps an HTML attribute as a Node-like object. In real DOM each attribute on an element is an Attr; `el.getAttributeNode` returns the instance, `attr.value = “x”` mutates the element’s attribute, ‘attr.ownerElement` points back to the element.

We represent two states:

- "owned" — the Attr is attached to an Element. value reads/writes
  go through the element's Nokogiri attribute slot.
- "detached" — created via `document.createAttribute(name)` but
  not yet attached. Value is stored locally; `setAttributeNode`
  transfers it to an element.

Constant Summary collapse

JS_METHOD_NAMES =

Methods routed through js_call (keep in sync with its when-arms).

%w[cloneNode].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, owner: nil, value: "") ⇒ Attr

Returns a new instance of Attr.



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# File 'lib/dommy/attr.rb', line 18

def initialize(name, owner: nil, value: "")
  @name = name.to_s.downcase
  @owner = owner
  @detached_value = value.to_s
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/dommy/attr.rb', line 16

def name
  @name
end

Instance Method Details

#__internal_attach__(element) ⇒ Object

Internal: called by Element when the attr is being transferred to (or detached from) an Element.



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# File 'lib/dommy/attr.rb', line 90

def __internal_attach__(element)
  @owner = element
  @detached_value = ""
  nil
end

#__internal_detach__ ⇒ Object 



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# File 'lib/dommy/attr.rb', line 96

def __internal_detach__
  cached = value
  @owner = nil
  @detached_value = cached
  nil
end

#__js_call__(method, _args) ⇒ Object 



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# File 'lib/dommy/attr.rb', line 81

def __js_call__(method, _args)
  case method
  when "cloneNode"
    Attr.new(@name, owner: nil, value: value)
  end
end

#__js_get__(key) ⇒ Object 



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# File 'lib/dommy/attr.rb', line 45

def __js_get__(key)
  case key
  when "name"
    @name
  when "value"
    value
  when "nodeName"
    @name
  when "nodeValue"
    value
  when "ownerElement"
    @owner
  when "localName"
    @name
  when "namespaceURI"
    nil
  when "nodeType"
    2
  end
end

#__js_method_names__ ⇒ Object 



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# File 'lib/dommy/attr.rb', line 77

def __js_method_names__
  JS_METHOD_NAMES
end

#__js_set__(key, val) ⇒ Object 



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# File 'lib/dommy/attr.rb', line 66

def __js_set__(key, val)
  case key
  when "value", "nodeValue"
    self.value = val
  end

  nil
end

#owner_element ⇒ Object

The Element this attr is on, or nil if detached.



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# File 'lib/dommy/attr.rb', line 25

def owner_element
  @owner
end

#value ⇒ Object 



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# File 'lib/dommy/attr.rb', line 29

def value
  if @owner
    @owner.__dommy_backend_node__[@name].to_s
  else
    @detached_value
  end
end

#value=(new_value) ⇒ Object 



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# File 'lib/dommy/attr.rb', line 37

def value=(new_value)
  if @owner
    @owner.set_attribute(@name, new_value.to_s)
  else
    @detached_value = new_value.to_s
  end
end