TypeError: Cannot read properties of null (reading 'map')

[arnowelzel]

Describe the bug
When opening the Bookmarks app there are many errors in the console like these:

TypeError: Cannot read properties of null (reading 'map')
    at o.tags (bookmarks-src_components_ViewPrivate_vue.js?v=52acc5cac172546bf716:1:81202)
    at e.get (bookmarks-main.js?v=f215bb01-0:2:1148472)
    at e.evaluate (bookmarks-main.js?v=f215bb01-0:2:1149468)
    at o.tags (bookmarks-main.js?v=f215bb01-0:2:1161945)
    at fn (bookmarks-src_components_ViewPrivate_vue.js?v=52acc5cac172546bf716:1:84967)
    at i (bookmarks-main.js?v=f215bb01-0:2:1142234)
    at o.Ot [as _t] (bookmarks-main.js?v=f215bb01-0:2:1139482)
    at o.Ec (bookmarks-main.js?v=f215bb01-0:2:2416287)
    at e._render (bookmarks-main.js?v=f215bb01-0:2:1167936)
    at o.a (bookmarks-main.js?v=f215bb01-0:2:1197937)

A bad HTTP response code (404) was received when fetching the script.

bookmarks-main.js?v=f215bb01-0:2 TypeError: Failed to register a ServiceWorker for scope ('https://server.example/apps/bookmarks') with script ('https://server.example/index.php/apps/bookmarks/bookmarks-service-worker.js'): A bad HTTP response code (404) was received when fetching the script.

To Reproduce
Steps to reproduce the behavior:

1. Install Bookmarks on Nextcloud 31
2. Open the Bookmarks app
3. Check the JavaScript console for errors

Expected behavior
There are no errors.

Screenshots

Desktop (please complete the following information):

• OS: Windows 11
• Browser: Vivaldi, Chrome, Firefox
• Version: latest versions as of 2025-09-29

Server (please complete the following information):

• OS: Ubuntu 24.04
• HTTP server: Apache
• Database: MariaDB
• PHP version: 8.3
• Nextcloud version: 31.0.9
• Bookmarks app version: 15.2.0
• Activated Nextcloud Apps: -
• Nextcloud configuration: -
• Nextcloud external user backend: none

Additional context

Web server error log

Nextcloud log (nextcloud/data/nextcloud.log)

Browser log

Too long to be posted here - just an example:

bookmarks-main.js?v=dd39f1ee-81:2 TypeError: Cannot read properties of null (reading 'map')
    at o.tags (bookmarks-src_components_ViewPrivate_vue.js?v=52acc5cac172546bf716:1:81202)
    at e.get (bookmarks-main.js?v=dd39f1ee-81:2:1148472)
    at e.evaluate (bookmarks-main.js?v=dd39f1ee-81:2:1149468)
    at o.tags (bookmarks-main.js?v=dd39f1ee-81:2:1161945)
    at fn (bookmarks-src_components_ViewPrivate_vue.js?v=52acc5cac172546bf716:1:84967)
    at i (bookmarks-main.js?v=dd39f1ee-81:2:1142234)
    at o.Ot [as _t] (bookmarks-main.js?v=dd39f1ee-81:2:1139482)
    at o.Ec (bookmarks-main.js?v=dd39f1ee-81:2:2416287)
    at e._render (bookmarks-main.js?v=dd39f1ee-81:2:1167936)
    at o.a (bookmarks-main.js?v=dd39f1ee-81:2:1197937)
_n @ bookmarks-main.js?v=dd39f1ee-81:2
bookmarks-main.js?v=dd39f1ee-81:2 You need to fill either the text or the ariaLabel props in the button component. Object o
render @ bookmarks-main.js?v=dd39f1ee-81:2
bookmarks-main.js?v=dd39f1ee-81:2 TypeError: Cannot read properties of null (reading 'map')
    at o.tags (bookmarks-src_components_ViewPrivate_vue.js?v=52acc5cac172546bf716:1:81202)
    at e.get (bookmarks-main.js?v=dd39f1ee-81:2:1148472)
    at e.evaluate (bookmarks-main.js?v=dd39f1ee-81:2:1149468)
    at o.tags (bookmarks-main.js?v=dd39f1ee-81:2:1161945)
    at fn (bookmarks-src_components_ViewPrivate_vue.js?v=52acc5cac172546bf716:1:84967)
    at i (bookmarks-main.js?v=dd39f1ee-81:2:1142234)
    at o.Ot [as _t] (bookmarks-main.js?v=dd39f1ee-81:2:1139482)
    at o.Ec (bookmarks-main.js?v=dd39f1ee-81:2:2416287)
    at e._render (bookmarks-main.js?v=dd39f1ee-81:2:1167936)
    at o.a (bookmarks-main.js?v=dd39f1ee-81:2:1197937)
_n @ bookmarks-main.js?v=dd39f1ee-81:2
bookmarks-main.js?v=dd39f1ee-81:2 You need to fill either the text or the ariaLabel props in the button component. Object o
render @ bookmarks-main.js?v=dd39f1ee-81:2
bookmarks-main.js?v=dd39f1ee-81:2 TypeError: Cannot read properties of null (reading 'map')
    at o.tags (bookmarks-src_components_ViewPrivate_vue.js?v=52acc5cac172546bf716:1:81202)
    at e.get (bookmarks-main.js?v=dd39f1ee-81:2:1148472)
    at e.evaluate (bookmarks-main.js?v=dd39f1ee-81:2:1149468)
    at o.tags (bookmarks-main.js?v=dd39f1ee-81:2:1161945)
    at fn (bookmarks-src_components_ViewPrivate_vue.js?v=52acc5cac172546bf716:1:84967)
    at i (bookmarks-main.js?v=dd39f1ee-81:2:1142234)
    at o.Ot [as _t] (bookmarks-main.js?v=dd39f1ee-81:2:1139482)
    at o.Ec (bookmarks-main.js?v=dd39f1ee-81:2:2416287)
    at e._render (bookmarks-main.js?v=dd39f1ee-81:2:1167936)
    at o.a (bookmarks-main.js?v=dd39f1ee-81:2:1197937)
_n @ bookmarks-main.js?v=dd39f1ee-81:2

[github-actions]

Hello 👋

Thank you for taking the time to open this issue with the bookmarks app. I know it's frustrating when software
causes problems. You have made the right choice to come here and open an issue to make sure your problem gets looked at
and if possible solved.
I'm Marcel and have been maintaining this software the last few years. I currently work for Nextcloud but maintain this app
in my free time, because it is not an official Nextcloud product. My day job at Nextcloud is pretty awesome but sadly leaves me with
less time for side projects like this one than I used to have.
I still try to answer all issues and if possible fix all bugs here, but it sometimes takes a while until I get to it.
Until then, please be patient.
Note also that GitHub is a place where people meet to make software better together. Nobody here is under any obligation
to help you, solve your problems or deliver on any expectations or demands you may have, but if enough people come together we can
collaborate to make this software better. For everyone.
Thus, if you can, you could also look at other issues to see whether you can help other people with your knowledge
and experience. If you have coding experience it would also be awesome if you could step up to dive into the code and
try to fix the odd bug yourself. Everyone will be thankful for extra helping hands!
One last word: If you feel, at any point, like you need to vent, this is not the place for it; you can go to the forum,
to twitter or somewhere else. But this is a technical issue tracker, so please make sure to
focus on the tech and keep your opinions to yourself. (Also see our Code of Conduct. Really.)

I look forward to working with you on this issue
Cheers 💙

[marcelklehr]

Hi @arnowelzel
Thank you for taking the time to give feedback by opening this issue! These errors can mostly be ignored, but I will fix them nonetheless as they can be disconcerting for the casual onlooker :)

[arnowelzel]

Thank you!

Eventhough I understand, that some errors may not be serious, they should be handled nevertheless. If a property can be null, it must not be used without checking it first, since the triggered exception can have unexpected side effects. Also this makes it much harder to find errors when there is a support question and users are asked to send a log.

So as a rule of thumb: be strict with what you do in your code and expect the worst when using data which comes from other sources than your own code.

[marcelklehr]

Thank you for your wisdom.