function receivedMessage()

in node/app.js [218:316]
74 lines of code
18 McCabe index (conditional complexity)

function receivedMessage(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;
  var timeOfMessage = event.timestamp;
  var message = event.message;

  console.log("Received message for user %d and page %d at %d with message:", 
    senderID, recipientID, timeOfMessage);
  console.log(JSON.stringify(message));

  var isEcho = message.is_echo;
  var messageId = message.mid;
  var appId = message.app_id;
  var metadata = message.metadata;

  // You may get a text or attachment but not both
  var messageText = message.text;
  var messageAttachments = message.attachments;
  var quickReply = message.quick_reply;

  if (isEcho) {
    // Just logging message echoes to console
    console.log("Received echo for message %s and app %d with metadata %s", 
      messageId, appId, metadata);
    return;
  } else if (quickReply) {
    var quickReplyPayload = quickReply.payload;
    console.log("Quick reply for message %s with payload %s",
      messageId, quickReplyPayload);

    sendTextMessage(senderID, "Quick reply tapped");
    return;
  }

  if (messageText) {

    // If we receive a text message, check to see if it matches any special
    // keywords and send back the corresponding example. Otherwise, just echo
    // the text we received.
    switch (messageText) {
      case 'image':
        sendImageMessage(senderID);
        break;

      case 'gif':
        sendGifMessage(senderID);
        break;

      case 'audio':
        sendAudioMessage(senderID);
        break;

      case 'video':
        sendVideoMessage(senderID);
        break;

      case 'file':
        sendFileMessage(senderID);
        break;

      case 'button':
        sendButtonMessage(senderID);
        break;

      case 'generic':
        sendGenericMessage(senderID);
        break;

      case 'receipt':
        sendReceiptMessage(senderID);
        break;

      case 'quick reply':
        sendQuickReply(senderID);
        break;        

      case 'read receipt':
        sendReadReceipt(senderID);
        break;        

      case 'typing on':
        sendTypingOn(senderID);
        break;        

      case 'typing off':
        sendTypingOff(senderID);
        break;        

      case 'account linking':
        sendAccountLinking(senderID);
        break;

      default:
        sendTextMessage(senderID, messageText);
    }
  } else if (messageAttachments) {
    sendTextMessage(senderID, "Message with attachment received");
  }
}