convert html list to markdown list

lists.js

(function(ul, filter){

  var getGeneration = function(li){
    var f = function(li, count){
      var parent = li.parentNode;
      if (parent.nodeName !== 'UL'){
        return count - 1;
      }
      return f(parent.parentNode, ++count);
    }
    return f(li, 0);
  };

  var getIndent = function(indent){
    var r = "";
    for(var i = 0;i < indent;i++){
      r += '    ';
    }
    r += '- ';
    return r;
  };

  var re = [];
  var lis = document.querySelectorAll(ul);

  [].forEach.call(lis, function(node){
    var generation = getGeneration(node);
    var indentText = getIndent(generation);
    var text = node.textContent.trim().split('\n')[0];
    if(filter && !filter.test(text)) {
      return;
    }
    re.push(indentText + text);
  });

  return re;
})('.x-tree-node-ct li', /^filter/)

//.map((v)=>{return v.replace(/^            /, '')})
.join('\n')