Trouble with flow.get

General
1

Hi,

I am trying to use a switch in my UI and update the value of the switch (true or false) in a function node in another part of my flow. Based on the switch output, I am trying to use flow.get in the function node to set a variable. However, when I try to use flow.get, it just sets the variable in the function node to "null".

Below is my flow with the switch, and the code in the connected function node:

image

var btnOpOverride = msg.payload;
msg.payload = btnOpOverride;
return msg;

The code in the other function node in the flow looks like the following, but when I run this I get the default value for the first go around for the OperatorOverride variable, and then a "null" value the 2nd time around:

OperatorOverride = flow.get("btnOpOverride");

What am I doing wrong? I also tried some other things but nothing seems to work. I also tried doing flow.get and flow.set from the function node close to the switch, but that did not work either.

Thanks in advance for your help!

jstou

2

Somewhere you need to do
flow.set("btnOpOverride", somevalue)
otherwise flow.get has nothing to get.

3

Is this on another tab? If so, what you see is proper - go read Working with context : Node-RED

4

Thanks for the tip! It was not clear to me in the documentation that flow.get and flow.set could be in different function nodes, I thought they had to be in the same function node. Now it makes more sense!

5

No they are in the same flow. I've figured it out, I needed to use flow.set in the switch function node. I've read all these and they are helpful, but sometimes there is no answer online for a specific problem you are encountering...unless you ask for help on the Node Red Forum!!

6

If you want to retain data for re-use only within a single node (at a later time) then use context.get/set, if you want it to be accessible across multiple nodes in one flow (ie editor tab) then use flow.get/set, if you want to be able to access the data anywhere then use global.get/set

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