docs: function _prependPath(key, base) {
      if ((typeof key) === "number" || key.match(/^[0-9]+$/))
          key = "[" + key + "]";
      else if (!key.match(Match.IdentifierString) || _jsKeywords.indexOf(key) !== -1)
          key = JSON.stringify([key]);
  
      if (base && base[0] !== "[")
          return key + '.' + base;
      return key + base;
  }