读Zepto源码之Stack模块

'filter,add,not,eq,first,last,find,closest,parents,parent,children,siblings'.split(',').forEach(function(property) {
  var fn = $.fn[property]
  $.fn[property] = function() {
    var ret = fn.apply(this, arguments)
    ret.prevObject = this
    return ret
  }
})

$.fn.andSelf = function() {
  return this.add(this.prevObject || $())
}

$.fn.end = function() {
  return this.prevObject || $()
}