[Bug] orgTransform.apply is not a function - Loading json makes i18n fail in Vite 6.3.0

[jurgensweere]

Reporting a bug?

When you try to load additional json files in your project, not related to i18n, you get this error when using Vite 6.3.0

12:15:01 [vite] (client) Pre-transform error: orgTransform.apply is not a function
  Plugin: vite:json
  File: /home/projects/vitejs-vite-inmkmjbn/src/some.json
12:15:01 [vite] Internal server error: orgTransform.apply is not a function
  Plugin: vite:json
  File: /home/projects/vitejs-vite-inmkmjbn/src/some.json
      at jsonPlugin.transform (file:///home/projects/vitejs-vite-inmkmjbn/node_modules/@intlify/unplugin-vue-i18n/lib/index.mjs:278:33)
      at EnvironmentPluginContainer.transform (file:///home/projects/vitejs-vite-inmkmjbn/node_modules/vite/dist/node/chunks/dep-BuM4AdeL.js:42275:19)
      at async loadAndTransform (file:///home/projects/vitejs-vite-inmkmjbn/node_modules/vite/dist/node/chunks/dep-BuM4AdeL.js:35732:27)
      at async viteTransformMiddleware (file:///home/projects/vitejs-vite-inmkmjbn/node_modules/vite/dist/node/chunks/dep-BuM4AdeL.js:37230:24)

Expected behavior

No errors occurs

Reproduction

https://stackblitz.com/edit/vitejs-vite-inmkmjbn?file=src%2Frouter%2Findex.js&terminal=dev

Issue Package

unplugin-vue-i18n

System Info

System:
    OS: macOS 15.4
    CPU: (8) arm64 Apple M1 Pro
    Memory: 288.78 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.14.0 - ~/.nvm/versions/node/v22.14.0/bin/node
    npm: 10.9.2 - ~/.nvm/versions/node/v22.14.0/bin/npm
  Browsers:
    Chrome: 135.0.7049.95
    Edge: 135.0.3179.73
    Safari: 18.4
  npmPackages:
    vite: ^6.2.1 => 6.3.0 
    vue: ^3.4.27 => 3.5.13 
    vue-i18n: ^9.10.2 => 9.14.4

Screenshot

No response

Additional context

This might be due to the recently merged vitejs/vite#19586

Validations

• Read the Contributing Guidelines.
• Read the README
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion.

[sapphi-red]

We added a patch on Vite side for now. It should be working with 6.3.1.

But in Vite 7, I'd like to remove the patch. So I'd recommend updating this code to support jsonPlugin.transform.handler.

bundle-tools/packages/unplugin-vue-i18n/src/core/resource.ts

Lines 176 to 177 in d3724e1

	const orgTransform = jsonPlugin.transform
	jsonPlugin.transform = async function (code: string, id: string) {

[kazupon]

Thank you for your reporting!

I have some background on the part of the implementation in question,
When unplugin-vue-i18n was initially provided (from the time of the now-maintained-mote vite-plugin-vue-i18n), Vite (Rollup) did not support hook order and handler. So it is implemented like a hijack that overrides vite:json.

I believe that we can do the same thing by using the hook's order and handler. :)

[kazupon]

related issue
nuxt/nuxt#31812 (comment)

[YunYouJun]

It should be fixed in vitejs/vite#19878. Verification in the local project.

[jurgensweere]

I updated vite to 6.3.1 in the reproduction sample and that fixed the issue. You can close this bug or leave it open if you want to fix it to support Vite 7.

[kazupon]

I've just fixed this issue in v6.0.6.
Thanks guys!