Extract value from an object

[Paul Reed]

I'm playing with Lawrence's mobiUI, and struggling trying to extract the value (is it a json object?) from the dispatcher.

For example, the output from the dispatcher in the debug is;

(Object) {"id": "sld-1", "value": "19.3"}

I just want to retrieve the 19.3 as a msg.payload, so that it can be re-used.

Thanks. Paul

[Nicholas O'Leary]

Hi Paul,

you can use a Change node like this:

[{"id":"51ff7d89.ae0084","type":"change","action":"replace","property":"payload","from":"","to":"msg.payload.value","reg":false,"name":"","x":427,"y":379,"z":"85252611.7adad8","wires":[[]]}]

Or a function node:

    msg.payload = msg.payload.value;

    return msg;

Nick

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[Paul Reed]

With both, I get;

'TypeError: cannot read property 'value' of undefined'

[Nicholas O'Leary]

Paul,

is you debug node set to display the complete message object or just payload?

From that error, I'm guessing it is the former - I had assumed the latter in my original reply.

Try either of these:

[{"id":"51ff7d89.ae0084","type":"change","action":"replace","property":"payload","from":"","to":"msg.value","reg":false,"name":"","x":427,"y":379,"z":"85252611.7adad8","wires":[[]]}]

Function:

    msg.payload = msg.value;

    return msg;

On 4 October 2014 22:17, Paul Reed <paul...@gmail.com> wrote:

With both, I get;

'TypeError: cannot read property 'value' of undefined'

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[Paul Reed]

Yes, you are correct - complete message.

Your latest works and does exactly what I want, Thanks.

Paul

[Dave C-J]

We should maybe make the tiny (topic) text in debug say "complete message"... when in that mode to help ?

[Nicholas O'Leary]

Dave,

 Anna is on the case: https://github.com/node-red/node-red/pull/422

N

On 4 October 2014 23:19, Dave C-J <dce...@gmail.com> wrote:

We should maybe make the tiny (topic) text in debug say "complete message"... when in that mode to help ?

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[Dave C-J]

Great !
(And the other potential debug pr (reverse highlighting) looks good too.)

[Lawrence Griffiths]

Paul are you modifying the dispatcher javascript or using one it's outputs?

in dispatcher JavaScript

you can access both id and value 

obj.id

obj.v

On the outbound msg to another node what is passed is

msg.id

msg.value 

so changing the slider on UI should give this in degbug window (Object) { "id": "sld-1", "value": "43" } 

I should probably use payload

Lawrence

[Paul Reed]

I was using the dispatcher's outputs, but I see what you mean, and by changing the javascrip to;

// slider  sld-1 - output 3

} else if(obj.id=="sld-1"){

msg.payload = obj.v;

return [null, null, msg, null];

I can get the value directly as an output, which makes things simpler (for me!!)

Paul

[Lawrence Griffiths]

Yep will update the init version I'm working on to use msg.payload

[Paul Reed]

Ha, I see that you've updated it to msg.playload!!!

Paul

[Lawrence Griffiths]

Yep but both ID & V are passed in payload.

So you may want to delete ID for nodes that just expect a value.

I've also created a version with secure user authentication.

I'm putting together a short blog on how to set it up, should have that done in the next week.

 

Lawrence

[Paul Reed]

You have 'playload' not 'payload' in the ui dispatcher (4 times!).

Paul

[Lawrence Griffiths]

Arr will change thanks not enough time to test....