fix(nuxi): keep cwd at project root during preview

[Davidson3556]

🔗 Linked issue

resolves nuxt/nuxt#34397

📚 Description

nuxt preview was spawning the server with cwd set to the .output directory,
which means process.cwd() inside server handlers returns .output instead of
the project root. This is inconsistent with running node .output/server/index.mjs
directly, which keeps the cwd at project root.

The fix keeps cwd as the project root when spawning the preview server, and
resolves the server entrypoint args to absolute paths using outputPath so they
work without needing a chdir.

[github-actions]

📦 Bundle Size Comparison

📈 nuxi

Metric	Base	Head	Diff
Rendered	3698.84 KB	3698.90 KB	+0.05 KB (+0.00%)

📈 nuxt-cli

Metric	Base	Head	Diff
Rendered	138.81 KB	138.85 KB	+0.04 KB (+0.03%)

➡️ create-nuxt

Metric	Base	Head	Diff
Rendered	1645.98 KB	1645.98 KB	0.00 KB (0.00%)

[pkg-pr-new]

• nuxt-cli-playground

  npm i https://pkg.pr.new/create-nuxt@1235
  

  npm i https://pkg.pr.new/nuxi@1235
  

  npm i https://pkg.pr.new/@nuxt/cli@1235
  

commit: 2782704

[coderabbitai]

📝 Walkthrough

Walkthrough

The preview command in the Nuxi CLI is modified to execute with a working directory set to the provided project root (cwd) instead of the Nitro build output directory. Arguments are mapped to resolve paths that exist under the Nitro output directory, while other arguments remain unchanged. Working directory display in user-facing messages is updated to reflect this change. Minor imports and formatting adjustments are included.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: keeping the cwd at the project root during preview, which is the core fix in this changeset.
Description check	✅ Passed	The description is directly related to the changeset, explaining the problem (cwd set to .output directory), the impact (process.cwd() returns .output instead of project root), and the solution (keep cwd at project root and resolve args to absolute paths).
Linked Issues check	✅ Passed	The changes directly address the objectives from issue #34397 by keeping cwd at project root during preview, making it consistent with nuxt dev and direct node execution, and resolving server entrypoint arguments to absolute paths.
Out of Scope Changes check	✅ Passed	All changes in the preview.ts file are focused on fixing the working directory behavior and resolving arguments to absolute paths, which are directly aligned with the objectives of the linked issue.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[codspeed-hq]

Merging this PR will not alter performance

✅ 2 untouched benchmarks

---

_{Comparing Davidson3556:main (2782704) with main (d2fddf7)}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (main@d2fddf7). Learn more about missing BASE report.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1235   +/-   ##
=======================================
  Coverage        ?   45.42%           
=======================================
  Files           ?       46           
  Lines           ?     1070           
  Branches        ?      311           
=======================================
  Hits            ?      486           
  Misses          ?      475           
  Partials        ?      109           

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[coderabbitai]

🧹 Nitpick comments (1)

packages/nuxi/src/commands/preview.ts (1)

154-157: Splitting command by space may fail for paths containing spaces.

The .split(' ') approach assumes no spaces in the command path or arguments. While typical Nitro commands like node server/index.mjs are safe, paths with spaces would break. Consider using a shell-aware parser if this becomes an issue in practice.

💡 Optional: More robust parsing (if needed later)

If paths with spaces become a concern, consider using a proper shell parsing library or storing command and args separately in nitro.json:

-    const [cmd, ...cmdArgs] = nitroJSON.commands.preview.split(' ')
+    // If nitroJSON provides structured commands in future:
+    // const { cmd, args: cmdArgs } = nitroJSON.commands.preview
+    // For now, simple split is acceptable for typical node commands
+    const [cmd, ...cmdArgs] = nitroJSON.commands.preview.split(' ')

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/nuxi/src/commands/preview.ts` around lines 154 - 157, The preview
command currently splits nitroJSON.commands.preview by simple spaces which
breaks when the command or its args contain spaces; update the parsing logic
that assigns const [cmd, ...cmdArgs] = nitroJSON.commands.preview.split(' ') to
use a shell-aware parser (e.g., shell-quote or a small quoted-token parser) so
quoted paths remain intact, then map the resulting cmdArgs when computing
resolvedCmdArgs (the existsSync(join(outputPath, arg)) ? join(outputPath, arg) :
arg logic) as before; ensure the primary command token (cmd) and subsequent args
(cmdArgs/resolvedCmdArgs) are produced by the new parser so paths with spaces
are preserved.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@packages/nuxi/src/commands/preview.ts`:
- Around line 154-157: The preview command currently splits
nitroJSON.commands.preview by simple spaces which breaks when the command or its
args contain spaces; update the parsing logic that assigns const [cmd,
...cmdArgs] = nitroJSON.commands.preview.split(' ') to use a shell-aware parser
(e.g., shell-quote or a small quoted-token parser) so quoted paths remain
intact, then map the resulting cmdArgs when computing resolvedCmdArgs (the
existsSync(join(outputPath, arg)) ? join(outputPath, arg) : arg logic) as
before; ensure the primary command token (cmd) and subsequent args
(cmdArgs/resolvedCmdArgs) are produced by the new parser so paths with spaces
are preserved.

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ℹ️ Review info

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between d2fddf7 and 2782704.

📒 Files selected for processing (1)

• packages/nuxi/src/commands/preview.ts

[Davidson3556]

The runtimes.spec.ts failures on Windows are unrelated to this change — they're caused by a port conflict on the CI runner (port 3100 timeout). The same test suite passes for bun and deno runtimes, and the preview test in commands.spec.ts passes cleanly.