# How to delete a flow variable from a \`function\` node

**URL:** https://discourse.nodered.org/t/how-to-delete-a-flow-variable-from-a-function-node/19731
**Category:** General
**Created:** [30 December 2019 09:06 UTC](https://discourse.nodered.org/t/how-to-delete-a-flow-variable-from-a-function-node/19731 "2019-12-30T09:06:45Z")
**Posts on this page:** 1
**Showing post:** 10

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### Author: ![afelix](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/afelix/32/9743_2.png) [@afelix](https://discourse.nodered.org/u/afelix)
#### Post date: [30 December 2019 09:57 UTC](https://discourse.nodered.org/t/how-to-delete-a-flow-variable-from-a-function-node/19731/10 "2019-12-30T09:57:07Z")

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Because sometimes a picture says more than a thousand words:

 ![](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/7/707a9752ad18107cf0ff7f607ec568d212aebf9c.png)

`null` is the _assignment_ of the value “nothing” to a variable. `undefined` the _declaration_ of a variable without a value.

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_[View the full topic](https://discourse.nodered.org/t/how-to-delete-a-flow-variable-from-a-function-node/19731)._