[ottomated]

For adapter-cloudflare, we need to add @cloudflare/vite-plugin to the vite.plugins array. However, while configuring the plugin, we need access to svelte_config.out_dir in order to tell it how to generate the wrangler config.

This plugin allows adapters to do

  vite: ({ config }) => ({
    plugins: [
      some_plugin_that_requires(config),
    ]
  }

Drive-by, also allows adapters to just specify a plugins array if they don't need to specify pre and post. This is backwards-compatible.

---

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Summary by CodeRabbit

• New Features
  • Adapters can now configure Vite plugins dynamically using the validated SvelteKit configuration.
  • Added support for defining adapter Vite plugins as an ordered list or separate pre/post groups.
  • Expanded public adapter configuration types and documentation.
• Bug Fixes
  • Improved handling and ordering of adapter-provided Vite plugins.
• Documentation
  • Documented adapter Vite configuration options and plugin ordering.

[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from 0c1556e:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/0c1556ea1e5fb00cff14e219af3f0bbdb84a02ee

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16986

[changeset-bot]

🦋 Changeset detected

Latest commit: 0c1556e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-kit-16986-svelte.vercel.app/

[teemingc]

I feel a little conflicted about having the single array option default to pre. I kind of liked the explicitness of pre and post.

[ottomated]

I think pre and post are only needed in very rare situations; it would be confusing to adapter authors if we required the specificity when it actually doesn't matter most of the time.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Configuration used: defaults

Review profile: CHILL

Plan: Advanced

Run ID: 90057581-97c0-4664-823f-0dab8f363677

📥 Commits

Reviewing files that changed from the base of the PR and between 737984a and 0c1556e.

📒 Files selected for processing (7)

• .changeset/fifty-breads-judge.md
• packages/adapter-cloudflare/index.js
• packages/kit/src/core/config/index.js
• packages/kit/src/exports/public.d.ts
• packages/kit/src/exports/vite/index.js
• packages/kit/src/types/internal.d.ts
• packages/kit/types/index.d.ts

🚧 Files skipped from review as they are similar to previous changes (7)

• packages/kit/src/exports/vite/index.js
• .changeset/fifty-breads-judge.md
• packages/adapter-cloudflare/index.js
• packages/kit/types/index.d.ts
• packages/kit/src/core/config/index.js
• packages/kit/src/exports/public.d.ts
• packages/kit/src/types/internal.d.ts

Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review.

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📝 Walkthrough

Walkthrough

SvelteKit now supports adapter Vite configuration callbacks that receive the validated configuration. Vite plugin arrays are normalized as pre plugins, and the Cloudflare adapter uses this format.

Changes

Adapter Vite configuration

Layer / File(s)	Summary
Adapter Vite configuration contract packages/kit/src/exports/public.d.ts, packages/kit/types/index.d.ts, packages/kit/src/types/internal.d.ts	Adapter.vite accepts static configuration or a callback receiving ValidatedConfig. The exported AdapterViteConfig interface defines request, response, and ordered plugin options.
Validated adapter configuration packages/kit/src/core/config/index.js	validate_config invokes adapter.vite callbacks with the validated configuration and stores the returned options.
Vite plugin normalization and adapter wiring packages/kit/src/exports/vite/index.js, packages/adapter-cloudflare/index.js, .changeset/fifty-breads-judge.md	Array-valued plugins are normalized into pre plugins. The Cloudflare adapter passes its virtual-workers plugin as an array. A minor release changeset documents the update.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 0c155

This PR adds the requested adapter configuration flexibility and remains merge-ready after normal checks and review; no actionable merge-blocking risk remains.

Sequence Diagram(s)

sequenceDiagram
  participant Adapter
  participant validate_config
  participant Vite
  participant PluginAssembly
  Adapter->>validate_config: provide adapter.vite callback
  validate_config->>Adapter: request validated configuration
  Adapter-->>validate_config: return AdapterViteConfig
  validate_config->>Vite: store resolved Vite configuration
  Vite->>PluginAssembly: normalize plugin array as pre plugins
  PluginAssembly-->>Vite: assemble ordered plugins

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🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: adapters can provide Vite configuration through a function.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 6 files. (1 skipped: 1 …
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 6 files. (1 skipped: 1 unsupported.)

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch adapter-vite-function

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