Treat U+3000 as CJK punctuation-equivalent and make sure to recognize U+FF5E as CJK punctuation again in Markdown prose wrap by tats-u · Pull Request #18656 · prettier/prettier

tats-u · 2026-01-16T12:42:26Z

Description

Cherry-picked from #16805 (U+FF5E)

U+FF5E

U+3000

I noticed that U+FF5E ～ is not treated as a punctuation unlike U+301C 〜 (both are used in the same way in Japanese) in current Prettier by a failing test there. I should have fixed it in #16832, but a regression seems to have occurred.

https://prettier.io/playground/#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

Recent FIrefox added U+3000 to the CJ(K) punctuation list. I will add it to Prettier as a bonus, too.

<!-- Input (--prose-wrap=never) -->
测试 Test テスト Test
U+3000　
U+301C〜
U+FF5E～
U+1F221🈡

<!-- Prettier stable -->
测试 Test テスト Test U+3000　 U+301C〜U+FF5E～ U+1F221🈡

<!-- Prettier main -->
测试 Test テスト Test U+3000　U+301C〜U+FF5E～U+1F221🈡

Firefox preview for HTML (ja or zh is mandatory to trim spaces around these characters):

Checklist

I’ve added tests to confirm my change works.
(If changing the API or CLI) I’ve documented the changes I’ve made (in the docs/ directory).
(If the change is user-facing) I’ve added my changes to changelog_unreleased/*/XXXX.md file following changelog_unreleased/TEMPLATE.md.
I’ve read the contributing guidelines.

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fisker · 2026-01-16T13:43:06Z

Can you post an example, what will change?

If I'm not wrong, this will effect how sentence splits? In my experience, at least in Chinese, no one use U+3000 as punctuation, it's only used in one place, which is make alignment.

tats-u · 2026-01-16T13:54:01Z

no one use U+3000 as punctuation

Right, but if the line is ended with it, isn't it superfluous that an extra ASCII space is inserted after it when they are aggregated into one line?

　　Markdown初学者写的第一个Paragraph
　　Markdown初学者写的下一个段落。

↓

❌️　　Markdown初学者写的第一个Paragraph 　　Markdown初学者写的下一个段落。
✅️　　Markdown初学者写的第一个Paragraph　　Markdown初学者写的下一个段落。

Current Firefox's rule: biomejs/biome#7304 (comment)

fisker · 2026-01-16T14:19:05Z

Right, but if the line is ended with it, isn't it superfluous that an extra ASCII space is inserted after it when they are aggregated into one line?

So, this change means, only if u+3000 at end, it will not insert space when merge with next line? (I'm really sorry that I don't know enough about our markdown printer)

tats-u · 2026-01-16T14:39:37Z

it will not insert space when merge with next line?

Currently (without #16805), the writer must prefer to add a space between a han and an alphanumeric (applies to many Chinese and some Japanese; i.e. Prettier 2.x before #11597) to notify the change. Prettier (without #16805) will not insert a space even when it detects that style in (probably) a paragraph.

This change affects on the condition where proseWrap is other than preserve.

if u+3000 at end

\n → newline, [H] → han (or kana), [E] → non Han, [　] → U+3000, ␣ → U+0020

This change (for U+3000) only applies to the patterns when they are tried to be squashed into one line when Prettier detects the pre-#11597 style:

Pattern	Current	Changed to
`[　]\n[E]`	`[　]␣[E]`	`[　][E]`
`[E]\n[　]`	`[E]␣[　]`	`[E][　]`

They do not affect:

Pattern	Current	Changed to
`[　]\n[H]`	`[　][H]`	`[　][H]`
`[H]\n[　]`	`[H][　]`	`[H][　]`
`[　]\n[　]`	`[　][　]`	`[　][　]`

fisker · 2026-01-18T00:03:26Z

+await require('prettier').format('测试 Test テスト Test\nU+3000\u{3000}\nU+301C\u{301C}\nU+FF5E\u{FF5E}\nU+1F221\u{1F221}\n', {parser: 'markdown', proseWrap: 'always'});
+
+# Prettier stable
+// -> '测试 Test テスト Test\nU+3000\u{3000} \nU+301C\u{301C}\nU+FF5E\u{FF5E} \nU+1F221\u{1F221}\n'


Suggested change

// -> '测试 Test テスト Test\nU+3000\u{3000} \nU+301C\u{301C}\nU+FF5E\u{FF5E} \nU+1F221\u{1F221}\n'

// -> '测试 Test テスト Test\nU+3000\u{3000} \nU+301C\u{301C}\nU+FF5E\u{FF5E} \nU+1F221\u{1F221}\n'

// ^ extra space

Wait, this is not the real output, please actually run the code above and copy the print.

Since U+3000 is not visible, you can use this script

const output = await require('prettier').format('测试 Test テスト Test\nU+3000\u{3000}\nU+301C\u{301C}\nU+FF5E\u{FF5E}\nU+1F221\u{1F221}\n', {parser: 'markdown', proseWrap: 'always'}); [...output.slice(23, 26)].map(character => `\\u${character.codePointAt(0).toString(16)}`);

tats-u · 2026-01-18T01:00:18Z

Other than "测试" is https://github.com/yuru7/udev-gothic (Japanese font). The dotted squares are U+3000.

fisker

Thanks!

tats-u · 2026-01-18T01:15:44Z

Do we need  in the code block in the changelog Markdown?
The code await require('prettier').format('U+3000\u{3000}\nU+301C\u{301C}\nU+FF5E\u{FF5E}\nU+1F221\u{1F221} 测试 Test テスト\n', {parser: 'markdown', proseWrap: 'always'}); will be multi lines without it.

fisker · 2026-01-18T01:16:59Z

Do we need in the code block in the changelog Markdown?

No, since it's pure JS code.

tats-u · 2026-01-18T01:18:43Z

fisker · 2026-01-18T01:20:57Z

 ```js
-await prettier.format(
-  "测试 Test テスト Test\nU+3000\u{3000}\nU+301C\u{301C}\nU+FF5E\u{FF5E}\nU+1F221\u{1F221}\n",
+await require("prettier").format(


Use prettier instead of require("prettier").

Done, but you will have to run prettier = require("prettier").default in advance.

fisker · 2026-01-18T01:35:00Z

Thank you as always.

Make sure to recognize U+FF5E as punctuation

7dcd46a

tats-u changed the title ~~Make sure to recognize U+FF5E as punctuation~~ Make sure to recognize U+FF5E as punctuation again Jan 16, 2026

Add test

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tats-u force-pushed the ff5e-punct-2 branch from 6c93801 to 90870fb Compare January 16, 2026 13:17

Add changelog

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tats-u force-pushed the ff5e-punct-2 branch from 90870fb to 44d1163 Compare January 16, 2026 13:19

Treat U+3000 as punctuation

2589bb7

tats-u changed the title ~~Make sure to recognize U+FF5E as punctuation again~~ Treat U+3000 as punctuation and make sure to recognize U+FF5E as punctuation again Jan 16, 2026

Update changelog

250eb1c

tats-u changed the title ~~Treat U+3000 as punctuation and make sure to recognize U+FF5E as punctuation again~~ Treat U+3000 as punctuation and make sure to recognize U+FF5E as punctuation again in Markdown prose wrap Jan 16, 2026

tats-u changed the title ~~Treat U+3000 as punctuation and make sure to recognize U+FF5E as punctuation again in Markdown prose wrap~~ Treat U+3000 as CJK punctuation and make sure to recognize U+FF5E as CJK punctuation again in Markdown prose wrap Jan 16, 2026

tats-u changed the title ~~Treat U+3000 as CJK punctuation and make sure to recognize U+FF5E as CJK punctuation again in Markdown prose wrap~~ Treat U+3000 as CJK punctuation-equivalent and make sure to recognize U+FF5E as CJK punctuation again in Markdown prose wrap Jan 16, 2026

tats-u marked this pull request as draft January 16, 2026 15:46

fisker reviewed Jan 16, 2026

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Comment thread tests/format/markdown/splitCjkText/symbolSpaceNewLine.md Outdated

tats-u added 2 commits January 17, 2026 20:26

Move punctuation test to code

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tats-u marked this pull request as ready for review January 17, 2026 11:38

tats-u requested a review from fisker January 17, 2026 11:39

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Comment thread changelog_unreleased/markdown/18656.md

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Simplify changelog

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tats-u requested a review from fisker January 17, 2026 14:28

Replace .replaceAll with .replace for Node 14

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Update changelog description

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Use js as lang

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tats-u marked this pull request as draft January 18, 2026 01:13

Update example offending code

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tats-u marked this pull request as ready for review January 18, 2026 01:26

fisker merged commit 1f678ab into prettier:main Jan 18, 2026
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tats-u mentioned this pull request Jan 18, 2026

[v4+/Breaking Change] Make space and newline always interchangeable between Chinese/Japanese letter and non-Chinese-or-Japanese character in Markdown #16805

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	// -> '测试 Test テスト Test\nU+3000\u{3000} \nU+301C\u{301C}\nU+FF5E\u{FF5E} \nU+1F221\u{1F221}\n'
	// -> '测试 Test テスト Test\nU+3000\u{3000} \nU+301C\u{301C}\nU+FF5E\u{FF5E} \nU+1F221\u{1F221}\n'
	// ^ extra space

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