Incompatible with immutable Svelte compiler option

[imhul]

I have some bug with svelte-multiselect. Selected filters are not deleted by pressing the delete button. But in REPL is no bugs

REPL: https://svelte.dev/repl/2f17296c51504d2b82fe38c3f869aaba?version=3.55.1

video: https://drive.google.com/file/d/1E11B0vj93VMHY238QdvuD7bmBw7xo-B0/view?usp=sharing

[janosh]

Could you provide a repro? Either a REPL or StackBlitz would be great. You can click the readme badges to get you started:

[janosh]

@imhul The Google Drive link is not public, can't view the video. But like you said, looks like the REPL works fine.

[nosovk]

deletion.mp4

[janosh]

@nosovk Thanks for posting the video here. I see the problem. And you say the problem disappears when setting compilerOptions.immutable: false? I've never used that option myself. Is it generally compatible with Svelte? Svelte components tend to make use of mutability a lot...

[nosovk]

The default value for that option is false.

Temporary fix is:

on:remove={(e) => selected = [...selected]}

It's not about mutability, but about change detection:
https://svelte.dev/repl/4301a81c2ead4d85af7673bf9f1a16e8?version=3.16.4
check example above for better explanation.

[nosovk]

Another article with explanation why immutable is needed:
https://sveltesociety.dev/recipes/svelte-language-fundamentals/options-immutable

[janosh]

@imhul Ah, thanks for clarifying. That should be an easy fix.

[janosh]

Should be fixed by #196. No imminent release planned unless this is time critical?

[imhul]

Not a critical. Thank you very much for your help