Gmail build tree multiple level lables

data.json

{
  "labels": [
    {
      "id": "CHAT",
      "name": "CHAT",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "SENT",
      "name": "SENT",
      "type": "system"
    },
    {
      "id": "INBOX",
      "name": "INBOX",
      "type": "system"
    },
    {
      "id": "IMPORTANT",
      "name": "IMPORTANT",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "TRASH",
      "name": "TRASH",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "DRAFT",
      "name": "DRAFT",
      "type": "system"
    },
    {
      "id": "SPAM",
      "name": "SPAM",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "CATEGORY_FORUMS",
      "name": "CATEGORY_FORUMS",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "CATEGORY_UPDATES",
      "name": "CATEGORY_UPDATES",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "CATEGORY_PERSONAL",
      "name": "CATEGORY_PERSONAL",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "CATEGORY_PROMOTIONS",
      "name": "CATEGORY_PROMOTIONS",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "CATEGORY_SOCIAL",
      "name": "CATEGORY_SOCIAL",
      "messageListVisibility": "hide",
      "labelListVisibility": "labelHide",
      "type": "system"
    },
    {
      "id": "STARRED",
      "name": "STARRED",
      "type": "system"
    },
    {
      "id": "UNREAD",
      "name": "UNREAD",
      "type": "system"
    },
    {
      "id": "Label_1132815994075013083",
      "name": "My/My 2",
      "messageListVisibility": "show",
      "labelListVisibility": "labelShow",
      "type": "user"
    },
    {
      "id": "Label_1568450317911142934",
      "name": "My",
      "messageListVisibility": "show",
      "labelListVisibility": "labelShow",
      "type": "user"
    },
    {
      "id": "Label_2119806523827933884",
      "name": "My/My 2/My 123 4/9/0/0/000/333/httml/My 123 4/9/0/0/000/454",
      "messageListVisibility": "show",
      "labelListVisibility": "labelShow",
      "type": "user"
    },
    {
      "id": "Label_3333821800168712846",
      "name": "My 2",
      "messageListVisibility": "show",
      "labelListVisibility": "labelShow",
      "type": "user"
    },
    {
      "id": "Label_3924464747358265414",
      "name": "My/My 2/My 123 4/9/0/0/000/333/httml",
      "messageListVisibility": "show",
      "labelListVisibility": "labelShow",
      "type": "user"
    },
    {
      "id": "Label_6033357805571224531",
      "name": "My 2/My 22",
      "type": "user"
    }
  ]
}

labelsParser.js

/**
** @name labelsParser
** @auth TPT
**/

const _ = require('underscore');
const HasNoChildren = '\HasNoChildren';
const HasChildren = '\HasChildren';
const labelSystem = `system`;
const labelUser = `user`;

function replacePath(str){
  try{
    if(!_.isString(str)){
        new Error('it\' must string');
    }

    str = str.replace(/\ |\//gi, function(matched){
      return '-';
    });

    return str.toLowerCase();
  }catch (e){
     throw err;
  }
 
}

/**
 * Takes a response from the Gmail API's GET message method and extracts all
 * the relevant data.
 * @param  {object} response
 * @return {object}
 */
module.exports = (response) =>  {
  // init result
  let result = {};
  // filter label as system type
  let sysLabels = _.filter(response.labels, lbs => {
    return lbs.type === labelSystem;
  });

  sysLabels = _.map(sysLabels, lbs => {
    return {
      attribs: [HasNoChildren],
      children: null,
      delimiter: "/",
      displayName: lbs.name,
      path: lbs.id
    }
  });

  // progressing category
  sysLabels = _.map(sysLabels, lbs => {
    if (lbs.path.includes('CATEGORY_')) {
      lbs.path = lbs.path.replace('CATEGORY_', '');
      lbs.displayName = lbs.displayName.replace('CATEGORY_', '');
    }
    
    return lbs;
  });

  sysLabels = _.indexBy(sysLabels, 'displayName');
  
  // filter all label as type = `user`
  let labels = _.filter(response.labels, lbs => {
    return lbs.type === labelUser;
  });
  // sort move root on top
  labels.sort((prv, cur) => {
    if (prv.name.length < cur.name.length) {
      // prv should come before cur in the sorted order
      return -1;
    } else if (prv.name.length > cur.name.length) {
      // prv should come after cur in the sorted order
      return 1;
    } else {
      // prv and cur are the same
      return 0;
    }
  });

  // make sure always have system label
  if(_.size(sysLabels) > 0){
    result = _.extend(result, sysLabels);
  }
  
  let labelsdup = _.filter(response.labels, lbs => {
    return lbs.type === labelUser;
  });
  // fill parent for label children
  while (labelsdup.length !== 0) {
    let label = labelsdup.shift();
    labels = labels.map(cur => {
      if (cur.id !== label.id && cur.name.length > label.name.length && cur.name.indexOf(label.name + '/') === 0) {
        cur['parent'] = label.id;
      } 
      if(!cur['parent']){
        cur['parent'] = null;
      }
      return cur;
    });
  }
  // map structure tree labels imap
  labels = _.map(labels, lbs => {
    return {
      attribs: null,
      children: {},
      delimiter: '/',
      displayName: lbs.name,
      id: lbs.id,
      path: replacePath(lbs.name),
      parent: lbs.parent
    }
  });
  // add properties attribs
  labelsdup = _.clone(labels);
  while (labelsdup.length !== 0) {
    let label = labelsdup.shift();
    labels = labels.map(cur => {
      if (cur.id === label.parent) {
        cur['attribs'] = [HasChildren];
        cur.children[label.path] = label;
      }
      if(cur['attribs']===null){
        cur['attribs'] = [HasNoChildren];
      }
      return cur;
    });
  }

  // remove all lables has parent
  labels = _.filter(labels, lbs => {
      return lbs.parent === null;
  });
  
  labels = _.indexBy(labels, 'path');
  result = _.extend(result, labels);  
  
  return result;
}