fix(types): accept readonly and as const inputs by harlan-zw · Pull Request #736 · unjs/unhead

harlan-zw · 2026-04-10T05:42:38Z

🔗 Linked issue

N/A

❓ Type of change

📚 Description

Schema struct types (SpeculationRules, MetaFlat) used mutable arrays (string[]) which rejected as const literals. Changed all user-facing arrays to readonly so both mutable and readonly inputs are accepted without wrappers.

Added DeepReadonly utility type applied to InferScript/InferLink return types so defineScript/defineLink also handle readonly generics correctly.

Re-exported defineLink/defineScript from all framework packages (@unhead/vue, @unhead/react, @unhead/solid-js, @unhead/svelte, @unhead/angular).

Fixed UseScriptOptions TS 6 compatibility where Pick<> on optional properties needs Partial<> wrapper to preserve optionality.

Summary by CodeRabbit

New Features
- defineLink and defineScript utilities are now exposed in Angular, React, Solid.js, Svelte, and Vue packages.
Improvements
- Type system tightened to make link, script, metadata, and speculation-rules shapes deeply readonly for stronger immutability guarantees.
Tests
- Added unit tests covering script and link patterns, including structured and readonly usages.

Schema struct types (SpeculationRules, MetaFlat) used mutable arrays which rejected `as const` literals. Changed all user-facing arrays to `readonly` so both mutable and readonly inputs are accepted. Added DeepReadonly utility applied to InferScript/InferLink return types so defineScript/defineLink also handle readonly generics. Re-exported defineLink/defineScript from all framework packages (@unhead/vue, @unhead/react, @unhead/solid-js, @unhead/svelte, @unhead/angular).

Pick<> on optional properties needs Partial<> wrapper in TS 6 to preserve optionality.

coderabbitai · 2026-04-10T05:42:53Z

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 9de20271-41fb-4a65-8dc5-9d0512b74f9f

📥 Commits

Reviewing files that changed from the base of the PR and between 8eb3f29 and 28a8e43.

📒 Files selected for processing (1)

packages/unhead/src/types/util.ts

📝 Walkthrough

Walkthrough

Adds re-exports defineLink and defineScript to multiple framework packages; introduces DeepReadonly<T>; converts several array types to readonly; makes inferred Link/Script types deeply readonly; relaxes some Vue UseScriptOptions; and adds tests and export manifest updates.

Changes

Cohort / File(s)	Summary
Framework Public API Exports `packages/angular/src/public-api.ts`, `packages/react/src/index.ts`, `packages/solid-js/src/index.ts`, `packages/svelte/src/index.ts`, `packages/vue/src/index.ts`	Re-export `defineLink` and `defineScript` from `unhead` in each framework package public API.
Type System Utilities `packages/unhead/src/types/util.ts`	Add exported `DeepReadonly<T>` generic type that recursively makes objects/arrays readonly while preserving functions/primitives.
Schema Type Inference `packages/unhead/src/types/schema/link.ts`, `packages/unhead/src/types/schema/script.ts`	Wrap resolved/inferred link and script shapes in `DeepReadonly<>`, changing inference results to deeply readonly types.
Schema Array Constraints `packages/unhead/src/types/schema/metaFlat.ts`, `packages/unhead/src/types/schema/struct/speculationRules.ts`	Convert several mutable array properties to `readonly` arrays (article/book author/tag, speculation rules prefetch/prerender/requires/urls, and nested rule arrays).
Vue Script Options `packages/vue/src/scripts/useScript.ts`	Make `use`, `eventContext`, and `beforeInit` optional in `UseScriptOptions` via `Partial<Pick<...>>`.
Tests / Export Manifests `packages/unhead/test/unit/define.test.ts`, `test/exports/react.yaml`, `test/exports/solid-js.yaml`, `test/exports/svelte.yaml`, `test/exports/vue.yaml`	Add/extend tests for `defineScript`/structured script payloads and `as const` patterns; update YAML export manifests to include `defineLink` and `defineScript`.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Possibly related PRs

fix: better type narrowing escape hatches for custom rel/type #735: Adds core defineLink / defineScript helpers that are re-exported here.
fix: proper script importmap & speculationrules handling #734: Overlapping changes to script/importmap/speculationrules typings affecting the same schema areas.
feat(types)!: enforce strict type narrowing for Link and Script unions #729: Related modifications to link and script type definitions in the schema layer.

Poem

🐰 I nibble types both firm and sweet,

I tuck readonly where arrays meet,
I hop across frameworks, near and far,
Re-exporting helpers like a little star,
A rabbit's clap for tidy code complete.

🚥 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
Description check	✅ Passed	The description covers all required sections: linked issue, type of change (bug fix selected), and detailed explanation of the changes made.
Title check	✅ Passed	The title 'fix(types): accept readonly and as const inputs' accurately summarizes the main change—updating TypeScript typings to accept readonly and as const inputs.

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github-actions · 2026-04-10T05:44:46Z

Bundle Size Analysis

Bundle	Size	Gzipped
Client (Minimal)	10.7 kB	4.4 kB
Server (Minimal)	10.6 kB	4.3 kB
Vue Client (Minimal)	11.8 kB	4.8 kB
Vue Server (Minimal)	11.6 kB	4.7 kB

Copilot

Pull request overview

This PR adjusts Unhead’s TypeScript types to better accept readonly / as const inputs during type narrowing (notably for scripts, links, metadata, and speculation rules), and re-exports defineLink/defineScript from framework wrapper packages.

Changes:

Make several schema “array” fields readonly to accept as const literals without casts/wrappers.
Introduce DeepReadonly and apply it to InferScript / InferLink to improve readonly-friendly narrowing.
Re-export defineLink / defineScript from framework packages and extend unit tests/export snapshots accordingly.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
test/exports/vue.yaml	Updates Vue package export snapshot to include `defineLink`/`defineScript`.
test/exports/svelte.yaml	Updates Svelte package export snapshot to include `defineLink`/`defineScript`.
test/exports/solid-js.yaml	Updates Solid package export snapshot to include `defineLink`/`defineScript`.
test/exports/react.yaml	Updates React package export snapshot to include `defineLink`/`defineScript`.
packages/vue/src/scripts/useScript.ts	Adjusts `UseScriptOptions` typing for TS 6 optionality behavior.
packages/vue/src/index.ts	Re-exports `defineLink`/`defineScript` from `unhead`.
packages/unhead/test/unit/define.test.ts	Adds compile-time/runtime coverage for readonly/as-const link/script patterns.
packages/unhead/src/types/util.ts	Adds `DeepReadonly` utility type for readonly-friendly inference.
packages/unhead/src/types/schema/struct/speculationRules.ts	Switches speculation rules arrays to `readonly` and updates related types.
packages/unhead/src/types/schema/script.ts	Applies `DeepReadonly` to `InferScript` results.
packages/unhead/src/types/schema/metaFlat.ts	Switches MetaFlat array fields to `readonly`.
packages/unhead/src/types/schema/link.ts	Applies `DeepReadonly` to `InferLink` results.
packages/svelte/src/index.ts	Re-exports `defineLink`/`defineScript` from `unhead`.
packages/solid-js/src/index.ts	Re-exports `defineLink`/`defineScript` from `unhead`.
packages/react/src/index.ts	Re-exports `defineLink`/`defineScript` from `unhead`.
packages/angular/src/public-api.ts	Re-exports `defineLink`/`defineScript` from `unhead`.

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+ * Used in type narrowing so that `defineScript`/`defineLink` accept both
+ * mutable and `as const` (readonly) inputs without touching schema types.


harlan-zw added 2 commits April 10, 2026 15:36

fix(vue): UseScriptOptions TS 6 compatibility

5adb604

Pick<> on optional properties needs Partial<> wrapper in TS 6 to preserve optionality.

harlan-zw added 2 commits April 10, 2026 15:46

test: update export snapshots for defineLink/defineScript re-exports

5f9f258

fix: correct export snapshot sort order for react

8eb3f29

harlan-zw requested a review from Copilot April 10, 2026 05:54

harlan-zw changed the title ~~fix: accept readonly and as const inputs in type narrowing~~ fix(types): accept readonly and as const inputs Apr 10, 2026

Copilot started reviewing on behalf of harlan-zw April 10, 2026 05:55 View session

Copilot AI reviewed Apr 10, 2026

View reviewed changes

Comment thread packages/unhead/src/types/util.ts Outdated

Comment on lines +31 to +32

* Used in type narrowing so that `defineScript`/`defineLink` accept both

* mutable and `as const` (readonly) inputs without touching schema types.

docs: fix DeepReadonly comment to match actual usage

28a8e43

harlan-zw merged commit 5ccf98e into main Apr 10, 2026
8 checks passed

coderabbitai Bot mentioned this pull request May 27, 2026

fix(types): support union rel/type in defineLink and defineScript #765

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fix(types): accept readonly and as const inputs#736

fix(types): accept readonly and as const inputs#736
harlan-zw merged 5 commits into
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harlan-zw commented Apr 10, 2026 •

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		* Used in type narrowing so that `defineScript`/`defineLink` accept both
		* mutable and `as const` (readonly) inputs without touching schema types.

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harlan-zw commented Apr 10, 2026 • edited by coderabbitai Bot Loading Uh oh! There was an error while loading. Please reload this page.

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harlan-zw commented Apr 10, 2026 •

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