Different inline behavior when script is lang="ts"

[zhuha0yu]

Related plugins

• plugin-vue

• plugin-vue-jsx

Describe the bug

When building a component library using Vite and plugin-vue, I've noticed that when script block is set lang="ts", a Vue SFC would be compiled into two files:

The second file with Options API contains all options and would be used in the first file, As shown in Text3.
The second file with Composition API contains only a simple import and output statements, and is not USED.

After reviewing source code of this plugin, I've noticed that on packages/plugin-vue/src/script.ts Line 112, canInlineMain function returns false when script language is ts in production mode. Is it a mistake? The comment said that If the script is js/ts and has no external src, it can be directly placed in the main module. Skip for build

I've made a reproduction repo,please feel free to use it. Thank you!

Reproduction

https://github.com/zhuha0yu/temp-vite-plugin-vue-issue

Steps to reproduce

just run pnpm run build and watch for build results.

System Info

System:
    OS: Windows 10 10.0.19045
    CPU: (16) x64 12th Gen Intel(R) Core(TM) i5-12600KF
    Memory: 33.27 GB / 63.81 GB
  npmPackages:
    @vitejs/plugin-vue: ^5.2.1 => 5.2.1
    vite: ^6.0.5 => 6.0.7

Used Package Manager

pnpm

Logs

No response

Validations

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

### Tasks

[edison1105]

I think there is no mistake here. ts can be inlined in the development environment might be because:

• The development server directly processes .ts files through Vite's built-in TypeScript transformation feature.
• The production environment requires complete TypeScript compilation, type checking, ensuring code optimization and compatibility, and might involve other build tools (e.g., tsc).

[sapphi-red]

I think this is working as intended, too.