# Changing global variables
**URL:** https://discourse.nodered.org/t/changing-global-variables/1872
**Category:** General
**Created:** [27 July 2018 18:46 UTC](https://discourse.nodered.org/t/changing-global-variables/1872 "2018-07-27T18:46:18Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@rtalmeida](https://discourse.nodered.org/u/rtalmeida)
#### Post date: [27 July 2018 18:46 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/1 "2018-07-27T18:46:18Z")
All,
I am new on Node-Red, thus I am sorry if the question is too stupid. I used node-red to build a Chatbot app that uses "text to speech" (voice) capabilities. I have defined a global variable called "speechOnOff", and I set it to "off" initially. As this is a chatbot, I want the users to commands the voice to be on / off by typing a simple sentence "speech on" or "speech off".
My idea is to change the global variable "speechOnOff" dynamically whenever the user commands it.
Is that possible to change a global variable in any function node different form the one I used to set it initially? I tried but I got an error message.
thanks a lot.
---
### Author:  [@Andrei](https://discourse.nodered.org/u/Andrei)
#### Post date: [27 July 2018 18:51 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/2 "2018-07-27T18:51:51Z")
Indeed, that is possible and should work. Please detail what is the error message you got so as we can understand and try to help you to find a fix.
---
### Author:  [@rtalmeida](https://discourse.nodered.org/u/rtalmeida)
#### Post date: [27 July 2018 18:58 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/3 "2018-07-27T18:58:08Z")
Thanks a lot Andrei. I declare the variable like that:
NODE 1: Initial Node
```auto
var publicVariables = {
speechOnOff: "Off"
}
global.set("publicVariables", publicVariables);
```
NODE 2: Then on a second node I test the command, and depending on what it is I set the same global variable to "On" or "Off":
```auto
if (msg.message == "speech on") {
var publicVariables = {
speechOnOff: "On"
}
global.set("publicVariables", publicVariables);
}
else if (msg.message == "speech off") {
var publicVariables = {
speechOnOff: "Off"
}
global.set("publicVariables", publicVariables);
}
```
Finally on third node I checked if the same variable is "on" or "off":
```auto
var publicVariables = global.get("publicVariables").publicVariables;
if (publicVariables.speechOnOff == "On") {
output=msg.payload;
msg.payload = {};
msg.payload.output = {text: [output]}
node.warn(msg.payload.output);
node.warn("Conversation output is:\n" + JSON.stringify(msg.payload))
/* node.send([null,msg]); */
output = msg.payload.output.text.join(' ');
msg.payload = output;
}
```
And this is the error I got: `TypeError: Cannot read property 'speechOnOff' of undefined`, which heppens at the third node.
---
### Author:  [@knolleary](https://discourse.nodered.org/u/knolleary)
#### Post date: [27 July 2018 19:15 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/4 "2018-07-27T19:15:20Z")
In your first two nodes, you set `publicVariables` to be an object that looks like this:
```auto
{
speechOnOff: "on/off"
}
```
In your third node, you get the property with this:
```auto
var publicVariables = global.get("publicVariables").publicVariables;
```
You are getting the `publicVariables` global context property and then trying to access a property of that object called `publicVariables` - which doesn't exist.
So that line should just be:
```auto
var publicVariables = global.get("publicVariables");
```
---
### Author:  [@rtalmeida](https://discourse.nodered.org/u/rtalmeida)
#### Post date: [27 July 2018 19:22 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/5 "2018-07-27T19:22:45Z")
Thanks a lot. I do not have the error any more. One more question: at the second node, for me to change the value of the global variable, is it correct the code below? I am asking, as it seems the variable is not being changed.
var publicVariables = {
speechOnOff: "On"
}
global.set("publicVariables", publicVariables);
---
### Author:  [@knolleary](https://discourse.nodered.org/u/knolleary)
#### Post date: [27 July 2018 19:32 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/6 "2018-07-27T19:32:04Z")
(quick tip, put triple backticks - ``` - before and after any code snippets so that they display properly - I've edited your previous post to add them)
The code is okay - so if it isn't doing what you think, I'd suggest adding some debug statements to check what you're getting. For example, are you sure `msg.message` is the property to be testing?
```auto
var publicVariable;
// log `msg.message` to debug sidebar so you can see what you have
node.warn(msg.message);
if (msg.message == "speech on") {
publicVariables = {
speechOnOff: "On"
}
global.set("publicVariables", publicVariables);
}
else if (msg.message == "speech off") {
publicVariables = {
speechOnOff: "Off"
}
global.set("publicVariables", publicVariables);
}
```
---
### Author:  [@rtalmeida](https://discourse.nodered.org/u/rtalmeida)
#### Post date: [27 July 2018 19:34 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/7 "2018-07-27T19:34:32Z")
Thanks a lot. I will do it. You are great.
---
### Author:  [@Andrei](https://discourse.nodered.org/u/Andrei)
#### Post date: [27 July 2018 19:40 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/8 "2018-07-27T19:40:36Z")
Indeed nothing wrong with the code. I tested your second function and it is loading the global variable with an object according to the value of msg.message
```auto
[{"id":"f6a0a4b4.33beb8","type":"tab","label":"Flow 3","disabled":false,"info":""},{"id":"248936c9.f4b12a","type":"debug","z":"f6a0a4b4.33beb8","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"check","x":870,"y":360,"wires":[]},{"id":"3cef16e4.3c021a","type":"function","z":"f6a0a4b4.33beb8","name":"Second Function","func":"\nif (msg.message == \"speech on\") {\n \n var publicVariables = {\n speechOnOff: \"On\"\n }\n global.set(\"publicVariables\", publicVariables);\n}\nelse if (msg.message == \"speech off\") {\n \n var publicVariables = {\n speechOnOff: \"Off\"\n }\n global.set(\"publicVariables\", publicVariables);\n}\nreturn msg;","outputs":1,"noerr":0,"x":550,"y":280,"wires":[["ddc8ec64.70f6"]]},{"id":"975438f6.3aa918","type":"inject","z":"f6a0a4b4.33beb8","name":"","topic":"","payload":"speech on","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":140,"y":260,"wires":[["3f3265e9.a6205a"]]},{"id":"771aa6ad.91b118","type":"inject","z":"f6a0a4b4.33beb8","name":"","topic":"","payload":"speech off","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":140,"y":300,"wires":[["3f3265e9.a6205a"]]},{"id":"3f3265e9.a6205a","type":"change","z":"f6a0a4b4.33beb8","name":"","rules":[{"t":"set","p":"message","pt":"msg","to":"payload","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":330,"y":280,"wires":[["3cef16e4.3c021a"]]},{"id":"ddc8ec64.70f6","type":"function","z":"f6a0a4b4.33beb8","name":"Retrieve value from global context","func":"msg.check = global.get(\"publicVariables\");\nreturn msg;","outputs":1,"noerr":0,"x":640,"y":360,"wires":[["248936c9.f4b12a"]]}]
```
---
### Author:  [@rtalmeida](https://discourse.nodered.org/u/rtalmeida)
#### Post date: [27 July 2018 19:49 UTC](https://discourse.nodered.org/t/changing-global-variables/1872/9 "2018-07-27T19:49:45Z")
Thanks Andrei. Much appreciated.