func (t *Transformer) toMsg(incoming interface{}, msg *message.Msg) error { switch newMsg := incoming.(type) { case map[string]interface{}: // we're a proper message.Msg, so copy the data over msg.Op = message.OpTypeFromString(newMsg["op"].(string)) msg.Timestamp = newMsg["ts"].(int64) msg.Namespace = newMsg["ns"].(string) switch data := newMsg["data"].(type) { case otto.Value: exported, err := data.Export() if err != nil { t.pipe.Err <- t.transformerError(ERROR, err, msg) return nil } d, err := mejson.Unmarshal(exported.(map[string]interface{})) if err != nil { t.pipe.Err <- t.transformerError(ERROR, err, msg) return nil } msg.Data = map[string]interface{}(d) case map[string]interface{}: d, err := mejson.Unmarshal(data) if err != nil { t.pipe.Err <- t.transformerError(ERROR, err, msg) return nil } msg.Data = map[string]interface{}(d) default: msg.Data = data } case bool: // skip this doc if we're a bool and we're false if !newMsg { msg.Op = message.Noop return nil } default: // something went wrong return fmt.Errorf("returned doc was not a map[string]interface{}") } return nil }