1. DomName('SVGLengthList.insertItemBefore')
  2. DocsEditable()
Length insertItemBefore(Length item, int index)

Source 

@DomName('SVGLengthList.insertItemBefore')
@DocsEditable()
Length insertItemBefore(Length item, int index) => wrap_jso(_blink.BlinkSVGLengthList.instance.insertItemBefore_Callback_2_(unwrap_jso(this), unwrap_jso(item), index));