# Set variable in Change Node JSON

**URL:** <https://discourse.nodered.org/t/set-variable-in-change-node-json/31829>\
**Category:** General\
**Created:** [21 August 2020 12:08 UTC](https://discourse.nodered.org/t/set-variable-in-change-node-json/31829 "2020-08-21T12:08:13Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Hubertus](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/hubertus/32/10077_2.png) [@Hubertus](https://discourse.nodered.org/u/Hubertus)\
**Post date:** [21 August 2020 12:08 UTC](https://discourse.nodered.org/t/set-variable-in-change-node-json/31829/1 "2020-08-21T12:08:13Z")

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may bee a simple question - i have a change node:  
 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/c/8/c869d49d0d153119d2af8db7f2c7c184757af604.png)  
with the following JSON:

```auto
{
    "args": [
        21
    ]
}

```

now i have to set the "21" dynamicly e.g. with msg.payload. If i do so i get an error "Invalid Token".  
Or can i do thse same with a function node?

Thanks for any help  
BR  
Hubertus

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<div class="post-metadata">

**Author:** ![knolleary](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/knolleary/32/3_2.png) [@knolleary](https://discourse.nodered.org/u/knolleary)\
**Post date:** [21 August 2020 12:13 UTC](https://discourse.nodered.org/t/set-variable-in-change-node-json/31829/2 "2020-08-21T12:13:22Z")

</div>

Change the type of the field to "Expression" and replace the `21` with `payload`.

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<div class="post-metadata">

**Author:** ![Hubertus](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/hubertus/32/10077_2.png) [@Hubertus](https://discourse.nodered.org/u/Hubertus)\
**Post date:** [21 August 2020 12:28 UTC](https://discourse.nodered.org/t/set-variable-in-change-node-json/31829/3 "2020-08-21T12:28:27Z")

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Thank you . sometimes it's simple 😉  
Have a nice weekend

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [20 October 2020 12:28 UTC](https://discourse.nodered.org/t/set-variable-in-change-node-json/31829/4 "2020-10-20T12:28:32Z")

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Closed on 20 October 2020 12:28 UTC

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