# Javascript Object.keys() help
**URL:** https://discourse.nodered.org/t/javascript-object-keys-help/99934
**Category:** General
**Created:** [12 December 2025 10:14 UTC](https://discourse.nodered.org/t/javascript-object-keys-help/99934 "2025-12-12T10:14:11Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [12 December 2025 10:14 UTC](https://discourse.nodered.org/t/javascript-object-keys-help/99934/1 "2025-12-12T10:14:11Z")
I must be missing something obvious, can someone explain, please, how this code
```auto
const hasExtraProps = message => {
const allowed = ['_msgid', 'ui_update', 'class', 'visible', 'enabled']
console.log(`message: ${JSON.stringify(message)}`)
const keys = Object.keys(message)
console.log(`keys: ${JSON.stringify(keys)}`)
return keys.length > 0 && keys.some(key => !allowed.includes(key))
}
```
can show this in the log?
```auto
message: {"ui_update":{"color":"#E67E22"},"_msgid":"f047d5bf7047ad56"}
keys: ["ui_update","_msgid","payload"]
```
Where is the key "payload" coming from?
---
### Author:  [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)
#### Post date: [12 December 2025 11:04 UTC](https://discourse.nodered.org/t/javascript-object-keys-help/99934/2 "2025-12-12T11:04:01Z")
You would need to share the line that calls the function.
My initial guess would be that the input message has a `payload` property but that its value is `undefined`?
---
### Author:  [@knolleary](https://discourse.nodered.org/u/knolleary)
#### Post date: [12 December 2025 11:12 UTC](https://discourse.nodered.org/t/javascript-object-keys-help/99934/3 "2025-12-12T11:12:29Z")
> [@TotallyInformation](#):
>
> My initial guess would be that the input message has a `payload` property but that its value is `undefined`?
Agreed - that suggests `payload` has a value that isn't JSON encodable; could be `undefined`, could be some other object type that doesn't serialize.
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [12 December 2025 11:41 UTC](https://discourse.nodered.org/t/javascript-object-keys-help/99934/4 "2025-12-12T11:41:56Z")
Yes, you are exactly right, it is undefined. I had expected JSON.stringify() to show it with value undefined, but apparently not.
Thanks both.
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [26 December 2025 11:42 UTC](https://discourse.nodered.org/t/javascript-object-keys-help/99934/5 "2025-12-26T11:42:17Z")
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