jQuery plugin - find closest (inside / outside)

jQuery.findClosest.js

// http://stackoverflow.com/a/29823718/104380

jQuery.fn.findClosest = function (selector) {
    // If we have a :this selector
    var output = $(), 
        down = this.find(selector),
        siblings,
        recSearch,
        foundCount = 0;

    if(down.length) {
        output = output.add(down);
        foundCount += down.length;
    }

    // if all elements were found, return at this point
    if( foundCount == this.length )
      return output;

    siblings = this.siblings(selector);

    if( siblings.length) {
        output = output.add(siblings);
        foundCount += siblings.length;
    }

    // this is the expensive search path if there are still unfound elements

    if(foundCount < this.length){
        recSearch = rec(this.parent().parent());
        if( recSearch )
            output = output.add(recSearch);

    }

    function rec(elm){
        var result = elm.find(selector);
        if( result.length )
          return result;
        else
          rec(elm.parent());
    }

    return output;
};

// Test case

var buttons = $('a').findClosest('button');

console.log(buttons);

buttons.click(function(){
  this.style.outline = "1px solid red";
})