# (Brain failure) Need help understanding why it isn't working
**URL:** https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440
**Category:** General
**Created:** [21 July 2020 06:39 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440 "2020-07-21T06:39:46Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [21 July 2020 06:39 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/1 "2020-07-21T06:39:46Z")
I am trying to optimise how a `msg` is constructed.
This is what I have:
```auto
if (counter == 0)
{
msg = {
payload: "OFF",
icon: '',
background: "black"
};
} else
{
msg = {
payload: "ON",
icon: '',
background: "black"
};
}
```
My understanding is I can optimise it like this:
```auto
msg = {
icon: '',
background: "black"
};
if (counter == 0)
{
msg = {
payload: "OFF"
};
} else
{
msg = {
payload: "ON"
};
}
```
Or you could have it like this:
```auto
if (counter == 0)
{
msg = {
payload: "OFF"
};
} else
{
msg = {
payload: "ON"
};
}
msg = {
icon: '',
background: "black"
};
```
That way the `icon` and `background` are already set.
Just the `payload` changes.
It doesn't work.
Forgive my failure to remember why, but can you please explain why?
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [21 July 2020 07:02 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/2 "2020-07-21T07:02:05Z")
Where does `counter` come from?
> [@Trying\_to\_learn](#):
>
> It doesn't work.
because you set payload then destroy the original msg by doing this...
```auto
msg = {
icon: '',
background: "black"
};
```
Why not do this - much more clear and concise...
```auto
if (counter == 0) {
msg.payload = "OFF";
} else {
msg.payload = "ON";
}
msg.icon = '';
msg.background = "black";
```
EDIT...
it is much more preferable to update the existing msg than create new ones. It is more efficient and you retain (sometimes necessary) properties in the original msg.
---
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [21 July 2020 07:04 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/3 "2020-07-21T07:04:40Z")
Counter is set earlier on.
Isn't your second way the same as my second way?
I need a good slapping to get the brain working.
---
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [21 July 2020 07:06 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/4 "2020-07-21T07:06:42Z")
> [@Steve-Mcl](#):
>
> because you set payload then destroy the original msg by doing this...
>
> ```auto
> msg = {
> icon: '',
> background: "black"
> };
>
> ```
I don't see how that overwrites the original `payload` part of the message.
Sorry, I am trying to read your reply again.
Is it something to do with the `{ }` I use?
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [21 July 2020 07:10 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/5 "2020-07-21T07:10:27Z")
`msg = { ... }` // literally means "Create a NEW object"
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [21 July 2020 07:11 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/6 "2020-07-21T07:11:32Z")
> [@Trying\_to\_learn](#):
>
> Isn't your second way the same as my second way?
No
You destroy the original msg every time - I reuse it (as is the preferred way as far as I am concerned)
---
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [21 July 2020 07:12 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/7 "2020-07-21T07:12:05Z")
Yeah, ok. So the `{ }` were my _undoing_.
Thanks.
---
### Author:  [@bakman2](https://discourse.nodered.org/u/bakman2)
#### Post date: [21 July 2020 07:15 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/8 "2020-07-21T07:15:44Z")
Or shorter version
```auto
payload = counter === 0 ? "OFF" : "ON"
msg.icon = '';
msg.background = "black";
msg.payload = payload
return msg
```
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [21 July 2020 07:16 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/9 "2020-07-21T07:16:14Z")
Dont be throwing ternary confusion into the mix man 😃
---
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [21 July 2020 07:16 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/10 "2020-07-21T07:16:26Z")
You're just showing off now @bakman2😉
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [21 July 2020 07:17 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/11 "2020-07-21T07:17:01Z")
```auto
msg.icon = '';
msg.background = "black";
msg.payload = counter === 0 ? "OFF" : "ON";
return msg
```
Shorter @bakman2 😉
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [21 July 2020 07:18 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/12 "2020-07-21T07:18:08Z")
PS, your ternary is wrong way around 😉
---
### Author:  [@bakman2](https://discourse.nodered.org/u/bakman2)
#### Post date: [21 July 2020 07:18 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/13 "2020-07-21T07:18:37Z")
Ah yeah you are correct ; 🤖 but not anymore 😉
---
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [21 July 2020 07:20 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/14 "2020-07-21T07:20:19Z")
All this came about because I had buttons to control devices.
It was ok when there was only 1 button on 1 machine.
Now there are multiple machines with the button, when one changes the state, all machines have to update.
Of course that seemed easy at first, but then when the other machine's buttons were pressed the state was wrong and needed up dating.
Caused big problems and I had to rewrite a lot of stuff and conditional handling.
I was/am trying to cut down on redundant code. Though this is a bit petty, I think practice makes perfect. Or I can at least hope.
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [21 July 2020 07:44 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/15 "2020-07-21T07:44:09Z")
> [@Trying\_to\_learn](#):
>
> Yeah, ok. So the `{ }` were my _undoing_ .
No, it was the `msg =` that was your undoing. By saying that you throw away any current contents of `msg` and set it the value you specified.
By using `msg.payload = ` you are saying throw away any current data in `msg.payload` and replace it with a new value, leaving all other contents of `msg`, such as icon or background, as they were.
---
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [21 July 2020 07:45 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/16 "2020-07-21T07:45:29Z")
But it was other parts of the message which I was changing, conditional to the `payload` contents.
And neither of the bits of code I posted specified a new `payload`. Just that it was said that the `{ }` was saying build a new message from scratch.
Therefore the other parts are discarded.
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [21 July 2020 08:07 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/17 "2020-07-21T08:07:31Z")
> [@Colin](#):
>
> No, it was the `msg =` that was your undoing
Technically, Colin is correct.
Anything left of the `=` **is assignment**.
Its as simple as that.
the object/variable on the left of `=` is overwritten **in its entirety** at the point of execution.
But your statement...
> Yeah, ok. So the `{ }` were my _undoing_ "
... will suffice for your understanding of the situation.
---
### Author:  [@krambriw](https://discourse.nodered.org/u/krambriw)
#### Post date: [21 July 2020 08:27 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/18 "2020-07-21T08:27:07Z")
Would you not be interested in switching icons for on/off state as well???
---
### Author:  [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)
#### Post date: [21 July 2020 08:47 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/19 "2020-07-21T08:47:28Z")
> [@krambriw](#):
>
> Would you not be interested in switching icons for on/off state as well???
That is already in the system.
But the problem was because of multiple ~~devices~~ computers being able to control the one external device and all be in sync.
As said, the code sort of worked but then if another computer's button was pressed, it wasn't in sync.
This is an example:
Incoming messages of "ON" and "OFF" set the correct state of the switch.
Otherwise pressing the button (switch) an `X` message is local and toggles the button's condition.
```auto
[{"id":"9fb7e7ec.4e6b78","type":"switch","z":"26262ba1.62dcbc","name":"TOPICS *","property":"topic","propertyType":"msg","rules":[{"t":"eq","v":"BULB-1/cmnd/power1","vt":"str"},{"t":"eq","v":"BULB-1/cmnd/dimmer","vt":"str"},{"t":"else"}],"checkall":"true","repair":false,"outputs":3,"x":2660,"y":300,"wires":[["c0671188.49e67","b31baea6.87a2f"],["2eac36ef.582eca"],[]],"outputLabels":["State","","LWT"],"info":"This needs editing for different BULBS"},{"id":"c0671188.49e67","type":"function","z":"26262ba1.62dcbc","name":"Set state","func":"if (msg.payload == \"RESET\")\n{\n let state = context.get(\"STATE\");\n if (state === 0)\n {\n //\n msg= {icon: ''};\n msg.background = \"black\";\n return msg;\n } else\n {\n //\n msg= {icon: ''};\n msg.background = \"black\";\n return msg;\n }\n}\nif (msg.payload == \"ON\")\n{\n msg= {icon: ''};\n msg.background = \"black\";\n context.set(\"STATE\",1);\n} else\n{\n msg= {icon: ''};\n msg.background = \"black\";\n context.set(\"STATE\",0);\n}\nreturn msg;\n","outputs":1,"noerr":0,"x":2860,"y":340,"wires":[["22cee9b7.50c1ae","c8ea1741.fbff8"]]},{"id":"c8ea1741.fbff8","type":"ui_button","z":"26262ba1.62dcbc","name":"BULB#1","group":"7893c6c4.30ede","order":2,"width":"1","height":"3","passthru":false,"label":"{{msg.icon}}","tooltip":"","color":"","bgcolor":"{{msg.background}}","icon":"","payload":"X","payloadType":"str","topic":"","x":3070,"y":380,"wires":[["b31baea6.87a2f"]]},{"id":"b31baea6.87a2f","type":"function","z":"26262ba1.62dcbc","name":"Button control BULB1","func":"var msg1 = {};\nvar counter = context.get(\"counter\") || 0;\ncounter = (counter + 1) % 2;\ncontext.set(\"counter\",counter);\n\nvar x = msg.payload;\n\nif (x == \"ON\")\n{\n counter = 1;\n context.set(\"counter\",1);\n return;\n} else\nif (x == \"OFF\")\n{\n counter = 0;\n context.set(\"counter\",0);\n return;\n}\n\nif (x == \"X\")\n{\n //\n if (counter == 0)\n {\n msg = {\n payload: \"OFF\",\n };\n } else\n {\n msg = {\n payload: \"ON\",\n };\n }\n msg.icon = '';\n msg.background = \"black\";\n}\nreturn msg;\n","outputs":1,"noerr":0,"x":3110,"y":420,"wires":[["d71b2e38.587d3","43c6ebaa.d58c44","c8ea1741.fbff8"]]},{"id":"7893c6c4.30ede","type":"ui_group","z":"","name":"BULB-1","tab":"aa487daa.33c1c","order":4,"disp":true,"width":"4","collapse":false},{"id":"aa487daa.33c1c","type":"ui_tab","z":"","name":"Real_World_Control","icon":"dashboard","order":3,"disabled":false,"hidden":false}]
```
If you want I could include more of the flow, but basically it is looking at a `MQTT` in node and it transmits to a `MQTT OUT` node.
---
### Author:  [@krambriw](https://discourse.nodered.org/u/krambriw)
#### Post date: [21 July 2020 09:15 UTC](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440/20 "2020-07-21T09:15:47Z")
> [@Trying\_to\_learn](#):
>
> That is already in the system
OK, then it's fine, I did not see this happening in the code you showed earlier, no cow on the ice as we say here up in north
[Next page](https://discourse.nodered.org/t/brain-failure-need-help-understanding-why-it-isnt-working/30440.md?page=2)