refactor: add rolldown as dependency

[pi0]

Currently nitro has optional peer dependency on rolldown + oxc-transform (for OpenAPI route meta) and oxc-minify for legacy.

Vite v8 will be having dependency on rolldown, by adding rolldown dependency to nitro:

• Nitro + Vite => The install size will be practically reduced as we share rolldown dep
• Nitro CLI for API => Nitro has built-in rolldown dependency which increases DX!

Important

Current PR depends on rolldown/experimental imports. Although i tried to make use of dynamic imports to reduce chance of fatal issues in case of breaking changes, we will be waiting and immediately update to better rolldown/ subpath export when available.

/cc @TheAlexLichter @nitrojs/vite

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Project	Deployment	Actions	Updated (UTC)
nitro.build	Ready	Preview, Comment	Feb 5, 2026 8:10pm

[coderabbitai]

📝 Walkthrough

Walkthrough

Replaces oxc-minify/oxc-transform with rolldown, elevates rolldown to runtime dependency, and converts several build plugins and config to async with dynamic imports; updates public types to use rolldown equivalents.

Changes

Cohort / File(s)	Summary
Dependency Migration package.json	Removed oxc-minify & oxc-transform; added/moved rolldown to dependencies with normalized ^1.0.0-rc.3.
Plugin Async Refactoring src/build/plugins/oxc.ts, src/build/plugins/route-meta.ts	Converted oxc and routeMeta to async functions and replaced static imports with dynamic await import("rolldown/experimental") to obtain transformSync/minifySync.
Plugin Orchestration / Rollup Config src/build/plugins.ts, src/build/rollup/config.ts	Now await the async plugin factories (routeMeta(nitro), oxc({...})) before pushing into plugin arrays; minor addition of a cwd transform option and a TS expect-error comment.
Type Updates src/types/build.ts	Replaced oxc-minify/oxc-transform type imports with rolldown equivalents and updated OXCOptions.minify and OXCOptions.transform (refined jsx typing).

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• feat(vite): use srvx loader for preview #3999: Similar migration to rolldown and related adjustments to build/plugin initialization.
• feat: rolldownConfig #3887: Updates src/types/build.ts to use rolldown types, overlapping with the type changes here.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title follows conventional commits format with 'refactor:' prefix and clearly describes the main change of adding rolldown as a dependency.
Description check	✅ Passed	The description is directly related to the changeset, providing context about the dependency migration from oxc packages to rolldown and its benefits.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch refactor/rolldown-dep

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@package.json`:
- Line 78: The package.json lists "rolldown" in dependencies but it is a
build-time tool used only by Nitro's build process (see src/build/rolldown/ and
build plugins) and should be moved to devDependencies; update package.json by
removing "rolldown" from "dependencies" and adding the same version entry under
"devDependencies" (preserve the ^1.0.0-rc.3 version and any optionalPeerDep
usage), then run an install to update lockfile so consumers no longer get
rolldown at runtime.

🧹 Nitpick comments (1)

src/build/plugins/oxc.ts (1)

1-9: Align MinifyOptions type import to match the public API source.

OXCOptions in src/types/build.ts uses RolldownMinifyOptions from rolldown, but this file imports MinifyOptions from rolldown/experimental. To maintain consistency and avoid potential type divergence, import from the stable rolldown export instead, which is the canonical source for this type.

♻️ Suggested alignment

-import type { MinifyOptions } from "rolldown/experimental";
+import type { MinifyOptions } from "rolldown";
 import type { OXCOptions } from "nitro/types";
 import type { Plugin } from "rollup";
 
 export async function oxc(
   options: OXCOptions & { sourcemap: boolean; minify: boolean | MinifyOptions }
 ): Promise<Plugin> {

[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@src/build/rollup/config.ts`:
- Around line 28-29: The code passes an unsupported cwd option to
rolldown.transformSync (cwd: nitro.options.rootDir) with a `@ts-expect-error`;
remove this invalid option and the ts-expect-error and either (a) if path
resolution is required, move/configure the cwd at the InputOptions level used by
rolldown() / build() or (b) configure path resolution within the relevant plugin
instead of passing cwd to transformSync; update usages around transformSync and
nitro.options.rootDir accordingly so no ignored/unsupported options remain.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/nitrojs/nitro@4002

commit: 05a235d

[sandros94]

EDIT: Fixed in d3b1f7b

@pi0 shouldn't both output options be optional?

nitro/src/types/build.ts

Lines 13 to 19 in db30877

	export type RollupConfig = RollupInputOptions & {
	output: RollupOutputOptions;
	};
	export type RolldownConfig = RolldownInputOptions & {
	output: RolldownOutputOptions;
	};