fix: tree-shake modulepreload polyfill

[caoxiemeihao]

Description

This is a build optimization PR, which will recuce the bundle size.

Before

After

Additional context

Reproduce

This is often used for Electron App builds.
My Electron App 👉 electron-vite-vue.

export default {
  build: {
    minify: false,
    rollupOptions: {
      output: {
        // Here
        format: 'cjs',
      },
    },
  },
}

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[sapphi-red]

Do you have a reproduction? I checked with playground/legacy, but it seems to work without this PR.

[caoxiemeihao]

@sapphi-red You can set the value of format to 'cjs' to reproduce. This is often used for Electron App builds.

export default {
  build: {
    minify: false,
    rollupOptions: {
      output: {
        // Here
        format: 'cjs',
      },
    },
  },
}

[sapphi-red]

This was because when you disable minify, tree-shaking won't be enabled for esbuild.
esbuild repl without --tree-shaking
esbuild repl with --tree-shaking

Currently it seems it's not possible to set esbuild.treeShaking: true and build.minify: false at the same time.

[bluwy]

I'd be fine doing this way for now to take advantage of Rollup treeshaking instead of esbuild's

[sapphi-red]

__VITE_IS_MODERN__ is replaced in renderChunk hook. So it is not tree-shaked by rollup.
With this PR, it will be removed by esbuild's constant propergation (esbuild repl).

[bluwy]

Oh interesting, so esbuild has some sort of partial treeshaking by default, which seems to remove false && foo, but not if (false) foo (example). In our case this would be fine then.