const textNode = (input, cursor, curr)=>{
  const idx = input.indexOf('<', cursor);
  curr.tag.children.push({
    type:'text', text:input.substring(cursor, idx)
  });
  return idx;
};

const attributes = attrStr => {
  if(!attrStr) return null;
  const attrStack = [], reg = /(\w+-?\w+)(?:=(["'])(.*?)\2)?/g;
  let result;
  while (result = reg.exec(attrStr)){
    attrStack.push({key :result[1], value:result[3] || true});
  }
  return attrStack;
};


const elementNode = (input, cursor, idx, curr) => {
  let isClose = input[idx -1] === '/';
  let innerTagStr =  input.substring(cursor + 1, idx - (isClose ? 1 : 0));
  const[_, name, attrStr] = innerTagStr.match(/(\S+)\s+(\S+.*)/) || [undefined, innerTagStr, undefined];
  const attr = attributes(attrStr);
  const tag = {name, type:'node', attr, children:[]};
  curr.tag.children.push(tag);
  if(!isClose){
    return {tag, back:curr};
  }
  return curr;
};

const parser = input => {
  input = input.trim();
  const result = {name : 'ROOT', type:'node', children: []};

  let curr = {tag:result}, i = 0, j = input.length;

  while(i<j){
    const cursor = i;
    if(input[cursor] === '<'){
      const idx = input.indexOf('>', cursor);
      i = idx + 1;
      if(input[cursor + 1] ==='/'){
        curr = curr.back;
      }else{

        curr = elementNode(input, cursor, idx, curr);
      }
    }else i = textNode(input, cursor, curr);
  }

  return result;
};

console.log('---------', parser('<div style="width:100%">a<a href="#">b</a>c<img alt="이런그림"/>d</div>'));