chore: refactor flush and error

lib/individualCommands.js

@@ -107,6 +107,12 @@ Multi.prototype.quit = function quit () {
   return this
 }
 
+/**
+ * @description Return a function that receives the raw info data and convert to an object.
+ *
+ * @param {RedisClient} client
+ * @returns {function}
+ */
 function infoCallback (client) {
   return function (err, res) {
     if (err) {