mqtt stuff added

node_modules/mqtt/lib/validations.js

@@ -0,0 +1,52 @@
+'use strict'
+
+/**
+ * Validate a topic to see if it's valid or not.
+ * A topic is valid if it follow below rules:
+ * - Rule #1: If any part of the topic is not `+` or `#`, then it must not contain `+` and '#'
+ * - Rule #2: Part `#` must be located at the end of the mailbox
+ *
+ * @param {String} topic - A topic
+ * @returns {Boolean} If the topic is valid, returns true. Otherwise, returns false.
+ */
+function validateTopic (topic) {
+  var parts = topic.split('/')
+
+  for (var i = 0; i < parts.length; i++) {
+    if (parts[i] === '+') {
+      continue
+    }
+
+    if (parts[i] === '#') {
+      // for Rule #2
+      return i === parts.length - 1
+    }
+
+    if (parts[i].indexOf('+') !== -1 || parts[i].indexOf('#') !== -1) {
+      return false
+    }
+  }
+
+  return true
+}
+
+/**
+ * Validate an array of topics to see if any of them is valid or not
+  * @param {Array} topics - Array of topics
+ * @returns {String} If the topics is valid, returns null. Otherwise, returns the invalid one
+ */
+function validateTopics (topics) {
+  if (topics.length === 0) {
+    return 'empty_topic_list'
+  }
+  for (var i = 0; i < topics.length; i++) {
+    if (!validateTopic(topics[i])) {
+      return topics[i]
+    }
+  }
+  return null
+}
+
+module.exports = {
+  validateTopics: validateTopics
+}