userAgent device.type is undefined for Macos Apple silicon devices

[Milad1412]

Link to the code that reproduces this issue

https://github.com/Milad1412/reproduce_device_detection_issue

To Reproduce

1. On a MacOs device start application in either production or dev mode
2. see the log and you find the issue that device.type is undefined in the console log of server's terminal

Current vs. Expected behavior

I expect to see a valid value for type of device, while I see undefined on Mac.

Provide environment information

Operating System: MacOs 26.1
Browser: Chrome, Safari
pnpm: 10.18.3
node: 22.19.0

Which area(s) are affected? (Select all that apply)

Middleware

Which stage(s) are affected? (Select all that apply)

next dev (local), next build (local), next start (local)

Additional context

No response

[icyJoseph]

Hi,

https://nextjs.org/docs/app/api-reference/functions/userAgent#device indicates that the device.type may be undefined.

This unfortunately goes down one level of abstraction... the methods used by that object, come from, https://github.com/faisalman/ua-parser-js/tree/1.0.35#documentation - note the version 1.0.x - and as listed in that package's version ReadMe:

# Possible 'device.type':
console, mobile, tablet, smarttv, wearable, embedded

##########
# NOTE: 'desktop' is not a possible device type. 
# UAParser only reports info directly available from the UA string, which is not the case for 'desktop' device type.
# If you wish to detect desktop devices, you must handle the needed logic yourself.
# You can read more about it in this issue: https://github.com/faisalman/ua-parser-js/issues/182
##########

So what's happening is that that User Agent string, used by your browser in your device, just doesn't have any info to infer what device it is. Or at the very best, that version of ua-parser-js doesn't know how to extract it.