Missing variant warning in typescript

[schillerenrico]

Package

v4.x

Description

Hi, does anyone know why TypeScript suddenly started warning about a missing variant?
<UButton ... size="2xl" ...>

TypeScript reports:
Type '"2xl"' is not assignable to type '"sm" | "md" | "lg" | "xl" | "xs" | undefined'.ts-plugin(2322)

However, everything still works at runtime, and the variant is correctly configured by me in app.config.ts.

Is this likely caused by a dependency or type definition issue?

[tluma]

This is expected behavior, not a bug. In Nuxt UI v4, TypeScript types are generated at build time from the bundled theme files in #build/ui/. Custom variants added in app.config.ts are runtime configuration and don't automatically update the generated type definitions.

As documented in the component structure, types are derived from:

type ComponentName = ComponentConfig<typeof theme, AppConfig, 'componentName'>

Where theme comes from #build/ui/component-name, generated at build time. Your "2xl" size is runtime-only and not reflected in the types.

Workarounds:

1. Type assertion (quick fix):

   <UButton :size="'2xl' as any" />

2. Extend types manually - if there's a supported API for type augmentation, a maintainers would need to confirm the exact approach.

3. Use ui prop for full flexibility:

   <UButton size="xl" ui={{ base: 'text-3xl' }} />

The runtime behavior is correct because the app.config.ts variants are properly merged. TypeScript just can't infer them statically.

[schillerenrico]

Yesterday no error was caused in typescript just after updating (npm update) today the IDE has this typescript issue. So its definitly a dependency issue

[J-Michalek]

Have you tried running npx nuxt prepare or restarting the dev server? I'm seeing no issue the our playground, not sure if I will be able to help without a reproduction.

[schillerenrico]

Yes, the issue is still the same. When I revert to my build from yesterday and run npm install, there’s no problem. After running npm update today, the error occurs. It should be related to changes within that time frame. I can try to create a reproduction.

[github-actions]

Would you be able to provide a reproduction? 🙏

More info

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How can I create a reproduction?

We have templates to create a minimal reproduction:

• Nuxt: https://codesandbox.io/p/devbox/nuxt-ui-xgrzw5
• Vue: https://codesandbox.io/p/devbox/nuxt-ui-vue-f2qp34

Please ensure that the reproduction is as minimal as possible. See more details in our guide.

You might also find these other articles interesting and/or helpful:

• The Importance of Reproductions
• How to Generate a Minimal, Complete, and Verifiable Example

[benjamincanac]

@schillerenrico I just investigated this but couldn't reproduce either, a reproduction would help!

[schillerenrico]

Here is a minimal reproduction of my setup
https://github.com/schillerenrico/reproduction-nuxtui-variant-ts-error

using vsc the following error occurs