build-html crash (undefined.call) when transformIndexHtml is registered in object form (breaks vite-plugin-pwa) #3188

Describe the bug

Describe the bug

vp build fails with TypeError: Cannot read properties of undefined (reading 'call') from applyHtmlTransforms whenever a plugin registers transformIndexHtml in the object form (the Vite 5+ convention). vite-plugin-pwa (and likely other mainstream plugins) does exactly this, so the build is broken out of the box for any project using PWA.

Reproduction

Minimal repro with any custom plugin using the object form:

// vite.config.js
export default {
  plugins: [
    {
      name: 'repro',
      transformIndexHtml: {
        transform(html) {
          return html;
        },
      },
    },
  ],
};

Or simply add vite-plugin-pwa to the plugins.

Expected behavior

The build succeeds and the transformIndexHtml hook is invoked.

Actual behavior

error during build:
Build failed with 1 error:
[plugin vite:build-html]
TypeError: Cannot read properties of undefined (reading 'call')
    at applyHtmlTransforms (.../vite-plus-core/dist/vite/node/chunks/node.js:37604:26)
    at PluginContextImpl.generateBundle (.../vite-plus-core/dist/vite/node/chunks/node.js:37392:20)

Root cause

In @voidzero-dev/vite-plus-core@1.3.0, resolveHtmlTransforms reads the object-form hook via hook.handler:

function resolveHtmlTransforms(plugins) {
  // ...
  const hook = plugin.transformIndexHtml;
  if (!hook) continue;
  if (typeof hook === "function") normalHooks.push(hook);
  else {
    const handler = hook.handler;        // ← should be hook.transform
    if (hook.order === "pre") preHooks.push(handler);
    else if (hook.order === "post") postHooks.push(handler);
    else normalHooks.push(handler);
  }
}

Since Vite 5, the object form of transformIndexHtml uses the transform key (not handler). Plugins that register { transform(html, ctx) {...}, enforce: 'post' } (e.g. vite-plugin-pwa) therefore push undefined into the hooks array. applyHtmlTransforms then calls hook.call(pluginContext, html, ctx) on undefined and throws.

Suggested fix

const handler = hook.transform ?? hook.handler;

Optionally also map enforce/apply to pre/post ordering, mirroring Vite core semantics.

Environment

• @voidzero-dev/vite-plus: 1.3.0 (core 1.3.0)
• Bundled Vite: 8.3.4, rolldown 1.2.14
• vite-plugin-pwa: 1.3.0
• Node: 20.19+ / 22
• OS: Windows 11 (reproducible cross-platform)

Workaround

Locally patch node_modules/@voidzero-dev/vite-plus-core/dist/vite/node/chunks/node.js:

const handler = hook.transform ?? hook.handler;

Reproduction

https://gist.github.com/journeybyte/b116b514fcd59cf5f97728b41581a515

Steps to reproduce

1. npm i -D vite-plus@1.3.0 in any project
2. Create vite.config.js with the plugin from the gist (object-form transformIndexHtml)
3. Run vp build
4. Build fails with TypeError: Cannot read properties of undefined (reading 'call') from applyHtmlTransforms

System Info

$ vp --version

vp v1.3.0

Local vite-plus:
  vite-plus  v1.3.0

Tools:
  vite             v8.3.4
  rolldown         v1.2.14
  vitest           v5.0.5
  oxfmt            v0.73.0
  oxlint           v1.88.0
  oxlint-tsgolint  v7.0.2004
  tsdown           v0.23.1

$ vp env current

Node.js:
  Version    24.22.1
  Source     engines.node
  Bin Path   C:\Users\Zhang\AppData\Local\vite-plus\data\js_runtime\node\24.22.1\node.exe
  Installed  false
  Mode       managed

Package Manager:
  Name       pnpm
  Version    12.14.0
  Source     lockfile or config
  Bin Paths
    pnpm     C:\Users\Zhang\AppData\Local\vite-plus\data\package_manager\pnpm\12.14.0\pnpm\bin\pnpm.exe
    pnpx     C:\Users\Zhang\AppData\Local\vite-plus\data\package_manager\pnpm\12.14.0\pnpm\bin\pnpx.exe
  Installed  true
  Mode       managed

Used Package Manager

pnpm

Logs

$ vp build --debug

error during build:
Build failed with 1 error:

[plugin vite:build-html]
TypeError: Cannot read properties of undefined (reading 'call')
    at applyHtmlTransforms (@voidzero-dev/vite-plus-core/dist/vite/node/chunks/node.js:37604:26)
    at PluginContextImpl.generateBundle (@voidzero-dev/vite-plus-core/dist/vite/node/chunks/node.js:37392:20)

Validations

• Read the Contributing Guidelines.
• Check that there isn't already an issue for the same bug.
• Confirm this is a Vite+ issue and not an upstream issue (Vite, Vitest, tsdown, Rolldown, or Oxc).
• The provided reproduction is a minimal reproducible example.