fix(jsx): add undefined to optional properties

[iamandrewluca]

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

[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