svelte 5: non enumerable property is removed in unstate

[izznat]

Describe the bug

Invoking unstate inside $derived results to a nested prop value removed.

Reproduction

Please look at the +page.svelte file in the repo below.
Reproduction

Steps:

1. Open browser console, the error will occurs immediately.

Logs

+page.svelte:14 (3) ['hue', 'saturation', 'lightness']
+page.svelte:15 (3) ['hue', 'saturation', 'lightness'] 'unstate'
@zag-js_color-picker.js?v=0cf62db1:3391 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'getChannels')
    at getAreaChannels (@zag-js_color-picker.js?v=0cf62db1:3391:32)
    at Object.getAreaProps (@zag-js_color-picker.js?v=0cf62db1:3519:38)
    at +page.svelte:43:26
    at chunk-QT3JEXLR.js?v=437d8e57:2652:47
    at execute_signal_fn (chunk-MPTA7GKG.js?v=437d8e57:539:7)
    at execute_effect (chunk-MPTA7GKG.js?v=437d8e57:668:31)
    at schedule_effect (chunk-MPTA7GKG.js?v=437d8e57:740:5)
    at internal_create_effect (chunk-MPTA7GKG.js?v=437d8e57:1243:5)
    at render_effect (chunk-MPTA7GKG.js?v=437d8e57:1315:10)
    at Module.spread_attributes_effect (chunk-QT3JEXLR.js?v=437d8e57:2651:3)

System Info

System:
    OS: Linux 6.6 Pop!_OS 22.04 LTS
    CPU: (8) x64 AMD Ryzen 3 5300U with Radeon Graphics
    Memory: 2.48 GB / 9.56 GB
    Container: Yes
    Shell: 5.8.1 - /usr/bin/zsh
  Binaries:
    Node: 21.6.1 - ~/.proto/shims/node
    Yarn: 1.22.21 - ~/.proto/shims/yarn
    npm: 10.4.0 - ~/.proto/shims/npm
    pnpm: 8.14.3 - ~/.proto/shims/pnpm
  npmPackages:
    svelte: ^5.0.0-next.1 => 5.0.0-next.40

Severity

annoyance

[trueadm]

Please can you create as repro on the REPL rather than stackblitz? Thanks.

[izznat]

I'll try.

[izznat]

Here is the REPL.

It seems it occurs when a property is defined using Object.defineProperty and not set it to be enumerable. Because unstate / unwrap uses Object.keys to traverse the object. It doesn't have anything to do with $derived.

The solution in zag is to set enumerable to true for computed context properties. The solution in svelte is to use Object.getOwnPropertyNames instead of Object.keys inside the unwrap function.

[trueadm]

@izznatsir Thank you for that. Can you try out #10348 and see if it fixes your problem?

[izznat]

Confirmed it fixed my issue. Thanks!