Sending more than one keyname:value to MQTT out

[Jon Murphy]

How do I send more than one keyname & value to a MQTT out?  I feel like there is a simpler way then what I have below.

Within the function I am sending one value to emon/test/topic1 and the second value to emon/test/topic2.  Please ignore the delay node, I am trying to debug something else.

function block code

ValueToOutput1 = Math.round(Math.random()*10*100)/100;

ValueToOutput2 = Math.round(Math.random()*10*100)/100;

//  ^^^   thank you Paul R !!

msg1 = {};

msg1.topic = "emon/test/topic1";

msg1.payload = ValueToOutput1;

msg2 = {};

msg2.topic = "emon/test/topic2";

msg2.payload = ValueToOutput2;

return [msg1,msg2];

[Nicholas O'Leary]

By returning an array of messages, each one is sent from the corresponding output of the Function node.

However, if one of those messages is itself an array of messages, then each of those messages will be sent from the same output.

That's a long way of saying, if you did:

return [ [msg1,msg2] ];

Then you'd only need one output from the Function and it would send msg1 and msg2 to the MQTT Out node in turn.

More info on multiple outputs vs multiple messages in the docs: http://nodered.org/docs/writing-functions#multiple-outputs

Nick

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[Jon Murphy]

Hi Nick!

I'm not sure I quite understand multiple messages but I will do it!!  Out of curiosity - Is there a limit on how many messages can be sent to the MQTT out via multiple messages?

Thank you!!

Jon

[Jon Murphy]

I should have added some boundaries to my last question.  I am talking about 5 to 10 messages sent to MQTT out via multiple messages (not 1000's of messages!).

[Nicholas O'Leary]

No limit

Nick

[Dave C-J]

apart from memory on your device etc... 

[Jon Murphy]

I read thru the multiple messages multiple times and did the return [ [msg1,msg2] ].  All work great!  Thank you!

I was going down the path of these:

msg.payload = {"topic1":"5.24","topic2":"4.32”}

-or-

msg.payload = {"emon/test": {"topic1": "5.24","topic2": "3.24”}}

Should one of those worked?

Thanks again!  Jon

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From: Nicholas OLeary
Sent: August 11, 2016 at 3:52:24 PM CDT
To: Node-RED Mailing List
Subject: Re: [node-red] Sending more than one keyname:value to MQTT out

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