Stack_Impl_for_getElementsByClassName.js

(function(){
  var r = document.getRootNode();

  var stack = [], list = [];
  stack.push(r);

  while(stack.length > 0){    
    var top = stack.pop();
    
    if(top.childNodes.length > 0){
      Array.from(top.childNodes)
        .filter(e => e.nodeType == Node.ELEMENT_NODE)
        .forEach(e => {
        stack.push(e);
      });
    }
    if(top.classList && top.classList.contains("hoverable")){
    	list.push(top);
    }
  }
	console.log(list)
}())