code: function toJSON() {
      var s = this;
      var values = Object.assign({}, s.schema);
      Object.keys(values).forEach(function (key) {
        var isFunc = iftype.isFunction(values[key]);
  
        if (isFunc) {
          delete values[key];
        }
      });
      return values;
    }
docs: Convert to json.
  @returns {object} - JSON schema.