code: function serializeJsonParams(params) {
  
    var result = {}
    if (params) {
      for (var key in params) {
        if (_.isArray(params[key])) {
          result[key] = _.map(params[key], function(val) {
            return _.isObject(val) ? ejson.stringify(val) : val
          })
        } else if (_.isObject(params[key])) {
          result[key] = ejson.stringify(params[key])
        } else {
          result[key] = params[key]
        }
      }
    }
  
    return result
  }
docs: *************************************************************************************************
  @method serializeJsonParams
  @param {object} params -- xxx
  @returns {object} -- a new object with params json values serialized as json strings