code: function normalizeData(val) {
    if (val === 'true') {
      return true;
    }
  
    if (val === 'false') {
      return false;
    }
  
    if (val === Number(val).toString()) {
      return Number(val);
    }
  
    if (val === '' || val === 'null') {
      return null;
    }
  
    return val;
  }
docs: --------------------------------------------------------------------------
  Bootstrap (v4.3.1): dom/manipulator.js
  Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
  --------------------------------------------------------------------------