watchDebounced return incorrect oldValue

[asvishnyakov]

Describe the bug

There is difference in how will work refDebounced + watch and watchDebounced.

Let's say we have a series of value changes:

• initial value is 1
• then value is changed to 2
• then to 3.

1. If you will use refDebounced + watch, oldValue is the value of reference before modifications, i.e. 1 (which is expected)
2. If you will use watchDebounced, oldValue is the value of last modifiction, i.e. 2 (which is unexpected).

That's because watchDebounced simply filter all events until the last one before time expire.

Reproduction

https://stackblitz.com/edit/vitejs-vite-db5xkj/?file=src%2FApp.vue

System Info

System:
    OS: Windows 10 10.0.22621
    CPU: (8) x64 Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
    Memory: 3.79 GB / 15.91 GB
  Binaries:
    Node: 18.15.0 - C:\Program Files\nodejs\node.EXE
    Yarn: 3.6.1 - E:\storefront\vc-theme-b2b-vue\node_modules\.bin\yarn.CMD
    npm: 9.5.0 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Spartan (44.22621.2283.0), Chromium (117.0.2045.31)
    Internet Explorer: 11.0.22621.1
  npmPackages:
    @vueuse/components: ^10.1.2 => 10.4.1
    @vueuse/core: ^10.1.2 => 10.4.1
    @vueuse/head: ~0.9.8 => 0.9.8
    vue: ^3.3.4 => 3.3.4

Used Package Manager

yarn

Validations

• [X] Follow our Code of Conduct
• [X] Read the Contributing Guidelines.
• [X] Read the docs.
• [X] Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• [X] Make sure this is a VueUse issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/core instead.
• [X] Check that this is a concrete bug. For Q&A open a GitHub Discussion.
• [X] The provided reproduction is a minimal reproducible example of the bug.

[asvishnyakov]

Hey guys, any news on that?

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[rafaellehmkuhl]

Adding here that not only the problem is still there, but the workaround (refDebounced + watch) does not work for reactive objects.

[asvishnyakov]

@rafaellehmkuhl Please create separate issue with mention of this one to catch attention of the team. I don't believe they review closed issues

[mesqueeb]

I have the same bug. @antfu can you re-open?

[OrbisK]

Can you share an up to date reproduction @mesqueeb?