Working mqtt setup

src/connectMqtt.js

@@ -0,0 +1,57 @@
+// @flow
+import mqtt from "mqtt";
+
+// TODO: type mqtt.js
+
+export type MqttSettings = {
+  onReconnect?: (mqtt: Object) => void,
+  onDisconnect?: (mqtt: Object) => void,
+  onMessage?: (topic: string, message: Object) => void,
+  onMessageSent?: (topic: string, message: any) => void,
+  onConnect?: (mqtt: Object) => void,
+  subscribe?: Array<string>
+}
+
+export type MessageCallback = (topic: string, message: any) => void;
+
+export default function connectMqtt(
+  url: string,
+  settings: MqttSettings = {}
+): MessageCallback {
+  const client = mqtt.connect(url);
+  client.on("connect", () => {
+    if (settings.subscribe != null) {
+      client.subscribe(settings.subscribe);
+    }
+    if (settings.onConnect != null) {
+      settings.onConnect(client);
+    }
+  });
+  client.on("message", (topic, message) => {
+    if (settings.onMessage != null) {
+      settings.onMessage(topic, message);
+    }
+  });
+  client.on("offline", () => {
+    if (settings.onDisconnect != null) {
+      settings.onDisconnect(client);
+    }
+  });
+  client.on("close", () => {
+    if (settings.onDisconnect != null) {
+      settings.onDisconnect(client);
+    }
+  });
+  client.on("reconnect", () => {
+    if (settings.onReconnect != null) {
+      settings.onReconnect(client);
+    }
+  });
+  return (topic: string, message: any) => {
+    client.publish(topic, message, null, (error) => {
+      if (error == null && settings.onMessageSent != null) {
+        settings.onMessageSent(topic, message);
+      }
+    });
+  };
+}