async function connectToAwsIot()

in src/MQTTDisplay.js [184:227]
30 lines of code
1 McCabe index (conditional complexity)

  async function connectToAwsIot() {

    // mqtt clients require a unique clientId; we generate one below
    var clientId = 'mqtt-explorer-' + (Math.floor((Math.random() * 100000) + 1));

    // get credentials and, from them, extract key, secret key, and session token
    // Amplify's auth functionality makes this easy for us...
    var currentCredentials = await Auth.currentCredentials();
    var essentialCredentials = Auth.essentialCredentials(currentCredentials);
    
    // Create an MQTT client
    var newMqttClient = AWSIoTData.device({
      region: AWSConfiguration.region,
      host:AWSConfiguration.host,
      clientId: clientId,
      protocol: 'wss',
      maximumReconnectTimeMs: 8000,
      debug: true,
      accessKeyId:  essentialCredentials.accessKeyId,
      secretKey:    essentialCredentials.secretAccessKey,
      sessionToken: essentialCredentials.sessionToken
     });
    console.log('Subscriber trying to connect to AWS IoT for clientId:', clientId);
    // On connect, update status
    newMqttClient.on('connect', function() {
      setIsConnected(true);
      newMqttClient.subscribe(props.topic);
      console.log('Connected to AWS IoT for clientId:', clientId);
      console.log(`Subscribed to ${props.topic}`);
    
    });

    // add event handler for received messages
    newMqttClient.on('message', function(topic, payload) {
      var myDate =      new Date().toLocaleDateString() + " " + new Date().toLocaleTimeString();
      var newMessage =  `${myDate} - topic '${topic}' - \n ${payload.toString()}`;
      setMessages(prevMessages => [...prevMessages, newMessage]);
      console.log(newMessage);
    });

    // update state to track mqtt client
    setMqttClient(newMqttClient);

  }