Performance issues in v5 when opening with many options in spite of virtual list being enabled

[CHamalainen]

Hello, and thanks for a great package.

We are updating a project relying heavily on Svelecte to version 5, and suddenly run into performance issues with opening the select when having a lot of options, in spite of enabling the virtual list. In version 4 the performance is great with the same number of options.

Step to reproduce:

• Initialize a Svelecte component with Virtual List enabled and 8000+ options supplied
• The options are objects containing only the text and value key/value pairs.

Results:

• It takes around 3 seconds for the options to be rendered after the first click, while in version 4 it is instant.
• Increasing the options count increases the time it takes to be rendered, while reducing the options count reduces the rendering time
• Subsequent clicks are rendered instantly

Videos:

Svelecte version 5
https://github.com/user-attachments/assets/d912fa2c-01ea-4a99-85cc-2d67c572f8c7

Svelecte version 4
https://github.com/user-attachments/assets/1c69cc3e-8579-4447-8939-d57b17862b02

[mskocik]

Interesting 🤔 will look into it

[CHamalainen]

@mskocik Thank you for your quick reply 🙏 let me know if you need anything else, or if I can help out in any way!