# Delete persistent flow context variable
**URL:** https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121
**Category:** General
**Created:** [13 September 2018 14:24 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121 "2018-09-13T14:24:01Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@cymplecy](https://discourse.nodered.org/u/cymplecy)
#### Post date: [13 September 2018 14:24 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/1 "2018-09-13T14:24:01Z")
I'm using persistant storage and I created a flow.context object with the wrong name
I would like to delete it - whats the easiest way to do this -preferably without having to manually edit the storage file or even stop /start NodeRED
---
### Author:  [@knolleary](https://discourse.nodered.org/u/knolleary)
#### Post date: [13 September 2018 14:41 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/2 "2018-09-13T14:41:55Z")
Use a Change node configured to delete it.
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### Author:  [@Andrei](https://discourse.nodered.org/u/Andrei)
#### Post date: [13 September 2018 14:42 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/3 "2018-09-13T14:42:50Z")
Try to add a mini-flow (inject + change node) just to delete the global variable. Afterward refresh the context panel to see if the variable is gone.
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### Author:  [@cymplecy](https://discourse.nodered.org/u/cymplecy)
#### Post date: [13 September 2018 14:46 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/4 "2018-09-13T14:46:40Z")
Ta - worked fine 🙂
............
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### Author:  [@JayDickson](https://discourse.nodered.org/u/JayDickson)
#### Post date: [27 November 2018 20:00 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/6 "2018-11-27T20:00:37Z")
Hopefully this isn't a stupid question, but how could we go about this with a function node so I could feed it a variable name to nuke when it's no longer needed?
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### Author:  [@hotNipi](https://discourse.nodered.org/u/hotNipi)
#### Post date: [27 November 2018 20:06 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/7 "2018-11-27T20:06:29Z")
To remove completely:
`flow.set(msg.payload);`
`global.set(msg.payload);`
To clear properties but preserve object:
`global.set(msg.payload,null);`
To get rid of all what was in store:
```
var keys = global.keys();
for(var i=0;i
### Author:  [@knolleary](https://discourse.nodered.org/u/knolleary)
#### Post date: [27 November 2018 20:22 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/8 "2018-11-27T20:22:30Z")
> [@hotNipi](#):
>
> To remove completely:
> `flow.set(msg.payload);`
> `global.set(msg.payload);`
Technically it's:
```auto
flow.set(msg.payload, undefined);
global.set(msg.payload, undefined);
```
Omitting the `undefined` is fine, but you may prefer to be explicit so it's clear.
---
### Author:  [@martenjacobs](https://discourse.nodered.org/u/martenjacobs)
#### Post date: [25 December 2018 13:10 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/9 "2018-12-25T13:10:45Z")
@hotNipi and @knolleary are correct.
Please note that this behavior may not be what you'd expect when you've worked with javascript objects before.
Behavior with javascript objects:
```
var test = {};
test.foo = "bar";
Object.keys(test); // returns ['foo']
test.foo = undefined;
Object.keys(test); // returns ['foo']
delete test.foo;
Object.keys(test); // returns []
```
In Node-RED, setting a context variable to undefined actually does remove the key. This means it safe to use to remove keys you're not using anymore without leaking memory:
```
context.set("foo", "bar");
context.keys(); // returns ['foo']
context.set("foo", undefined);
context.keys(); // returns []
```
---
### Author:  [@apricotfarm](https://discourse.nodered.org/u/apricotfarm)
#### Post date: [31 May 2021 03:13 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/10 "2021-05-31T03:13:20Z")
THANK YOU for this. A simple answer, but wasn't obvious to a NR noob...saved me from some self-harm 🙂
---
### Author:  [@Hunter](https://discourse.nodered.org/u/Hunter)
#### Post date: [3 December 2021 22:33 UTC](https://discourse.nodered.org/t/delete-persistent-flow-context-variable/3121/11 "2021-12-03T22:33:12Z")
@hotNipi and @knolleary thanks. I was looking for this and didn't know things can be this easy 🙂