@vitejs/plugin-vue will remove the code comment when <script lang="ts">

Describe the bug

my vite plugin:

{
    name: 'client-only',
    transform(code, id, { ssr } = {}) {
        if (ssr) {
            // In ssr case, I need to do some transform according to the code comment. eg: //...
            return transform(code);
        }
    },
}

my vite config:

plugins: [
  vue(),
  clientOnly() // after the vue plugin
]

but I found if the *.vue’ file’s <script> with lang=‘ts’, the comment in code will be remove:

btw, the <script> without lang=‘ts’, will keep the comment

I try to trace the source code Its like doing something in options.compiler.rewriteDefault

How should I keep the comment? Thanks all

Reproduction

https://stackblitz.com/edit/vitejs-vite-myfppw?file=vite.config.ts&terminal=dev

System Info

System:
    OS: macOS 10.15.7
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    Memory: 636.03 MB / 16.00 GB
    Shell: 5.7.1 - /bin/zsh
  Binaries:
    Node: 16.4.1 - ~/.nvm/versions/node/v16.4.1/bin/node
    Yarn: 1.22.4 - /usr/local/bin/yarn
    npm: 7.18.1 - ~/.nvm/versions/node/v16.4.1/bin/npm
  Browsers:
    Chrome: 98.0.4758.102
    Safari: 14.0.3

Used Package Manager

yarn

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 https://github.com/vuejs/core instead.
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• The provided reproduction is a minimal reproducible example of the bug.

[l1shu]

TS in Vue is being processed via esbuild. esbuild drops comments by default (evanw/esbuild#221) and there isn’t a way to configure it, so I don’t think there’s a way around it, other than changing your strategy.

It seems like you’re doing something like https://github.com/bluwy/vite-plugin-iso-import though. Perhaps that might help.

Its helpful for me, Thanks, Stared 👍

[bluwy]

I don’t think this will be fixed by esbuild soon, and it may as well be intended behaviour for them, as custom comments usually shouldn’t affect the bundling output (except special pure comments etc). So I’ll close this for now.