fix(jsx): add undefined to optional properties

[unrevised6419]

close #6068

Allow TypeScript projects that have exactOptionalPropertyTypes option enabled to be able to pass explicit props with a value of undefined

https://www.typescriptlang.org/tsconfig/#exactOptionalPropertyTypes

Let's take for example React:

https://github.com/DefinitelyTyped/DefinitelyTyped/blob/b30cd2bf71cdef25085038b4a556211c23c16489/types/react/index.d.ts#L3446-L3729

Checklist:

• Ensure no any | undefined
• Ensure no undefined | undefined
• Run format after review

I advise reviewing one commit at a time.

• In the first commit, I change all multiline unions to single-line unions to make it easier to review changes (same line diff).
• The second commit adds undefined.
• The third one formats the file back.

Images

"exactOptionalPropertyTypes": false

"exactOptionalPropertyTypes": true

"exactOptionalPropertyTypes": true and fixed src?: string | undefined

Related:

• Problem typing optional props with exactOptionalPropertyTypes enabled in tsconfig #6532

Links:

• https://github.com/sindresorhus/type-fest/blob/main/source/undefined-on-partial-deep.d.ts
• https://gist.github.com/unrevised6419/8bdfca183fde610708685a60c2510b1e

Summary by CodeRabbit

• Refactor
  • Improved type clarity and consistency for JSX, HTML, SVG, and ARIA attribute properties by explicitly allowing undefined values for all optional attributes. This enhances type safety and developer experience when working with JSX elements.

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	100 kB	38 kB	34.3 kB
vue.global.prod.js	158 kB	57.8 kB	51.5 kB

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	46.4 kB	18.2 kB	16.6 kB
createApp	54.3 kB	21.2 kB	19.3 kB
createSSRApp	58.5 kB	22.9 kB	20.9 kB
defineCustomElement	59.2 kB	22.8 kB	20.7 kB
overall	68.4 kB	26.3 kB	24 kB

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commit: 0dc9169

[jh-leong]

LGTM

[coderabbitai]

Walkthrough

The changes update TypeScript interface definitions for JSX intrinsic element attributes in packages/runtime-dom/src/jsx.ts. All optional properties in HTML, SVG, ARIA, and reserved prop interfaces now explicitly include | undefined in their type signatures, aligning with TypeScript's --exactOptionalPropertyTypes requirements. No runtime logic is affected.

Changes

File(s)	Change Summary
packages/runtime-dom/src/jsx.ts	Added `

Assessment against linked issues

Objective	Addressed	Explanation
Add `	undefinedto all optional properties in JSX, HTML, SVG, ARIA, and reserved prop interfaces to support TypeScript's--exactOptionalPropertyTypes (#6068`)	✅

Poem

In the warren, TypeScript bunnies convened,
To add | undefined—their codebase now cleaned!
JSX and ARIA, HTML too,
All props are exact, no errors break through.
Now vue-tsc runs, with carrots to spare,
The rabbits rejoice—no bugs anywhere! 🥕

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Actionable comments posted: 0

🧹 Nitpick comments (1)

packages/runtime-dom/src/jsx.ts (1)

1-8: Nitpick: Document the exactOptionalPropertyTypes rationale
Consider enhancing the file header with a brief note explaining that these type changes support TypeScript’s --exactOptionalPropertyTypes compiler option and reference issue #6068 for context.

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📥 Commits

Reviewing files that changed from the base of the PR and between d0253a0 and 5372774.

📒 Files selected for processing (1)

• packages/runtime-dom/src/jsx.ts (9 hunks)

🧰 Additional context used

🧬 Code Graph Analysis (1)

packages/runtime-dom/src/jsx.ts (1)

packages/runtime-core/src/vnode.ts (1)

• VNodeRef (86-92)

🔇 Additional comments (6)

packages/runtime-dom/src/jsx.ts (6)

49-266: ARIA Attributes: Explicitly include undefined
All attributes in AriaAttributes now correctly include | undefined, satisfying --exactOptionalPropertyTypes requirements. This change aligns with React’s patterns and improves type safety.

---

277-349: Standard HTMLAttributes: Add | undefined for optional props
The core HTMLAttributes interface has been updated so that innerHTML, style, and all standard HTML props explicitly allow undefined. This ensures JSX consumers can pass undefined without type errors under strict optional property settings.

---

362-385: Anchor & Area HTML Attributes: Explicit undefined
Both AnchorHTMLAttributes and AreaHTMLAttributes have had their optional props (href, rel, etc.) updated to include | undefined. This is consistent with the PR goal and does not affect runtime behavior.

---

541-584: InputHTMLAttributes: Include | undefined across input props
The InputHTMLAttributes interface now explicitly adds | undefined to every optional field (accept, checked, placeholder, etc.). This ensures compatibility with stricter TS settings when passing undefined to inputs.

---

835-862: SVGAttributes: Explicitly allow undefined on SVG props
All SVG-specific props (color, height, width, role, tabindex, etc.) now include | undefined, matching HTML and ARIA interfaces. Good coverage for strict optional types.

---

1425-1430: ReservedProps: Add | undefined to key/ref props
The ReservedProps type (key, ref, ref_for, ref_key) now explicitly allows undefined, aligning with the rest of the JSX prop types.

[unrevised6419]

What's the status with this PR? Do I need to add anything else?