@peaceroad/markdown-it-cjk-breaks-mod

@peaceroad/markdown-it-cjk-breaks-mod is a markdown-it plugin that suppresses line breaks between CJK text and optionally injects spacing after configured punctuation when a break is removed. It is designed for mixed Japanese/CJK + ASCII documents where default newline handling often produces unwanted spaces or breaks.

This package is a fork lineage of markdown-it-cjk-breaks and @sup39/markdown-it-cjk-breaks. It keeps the original CJK break suppression behavior, adds the either mode introduced by @sup39, and extends it with punctuation-spacing controls and softbreak normalization for plugin-heavy markdown-it pipelines.

Install

npm i @peaceroad/markdown-it-cjk-breaks-mod

Quick Start

import MarkdownIt from 'markdown-it';
import cjkBreaks from '@peaceroad/markdown-it-cjk-breaks-mod';

const md = MarkdownIt({ html: true }).use(cjkBreaks);

md.render('あおえ\nうい');
// <p>あおえうい</p>

Options

• either
  Type: boolean
  Default: false
  Remove a break when either side (instead of both sides) is CJK-width (F/W/H), still excluding Hangul.
  Origin: inherited from @sup39/markdown-it-cjk-breaks.

The options below are extensions added by this project:

• normalizeSoftBreaks
  Type: boolean
  Default: false
  Split newline-containing text tokens into explicit softbreak tokens before processing. Useful with plugins that rewrite inline tokens.
• spaceAfterPunctuation
  Type: 'half' | 'full' | string
  Default: disabled
  Insert spacing only when this plugin removes a break after a target sequence. 'half' => ' ', 'full' => \u3000.
• spaceAfterPunctuationTargets
  Type: string | string[] | [] | null | false
  Default: ['！', '？', '⁉', '！？', '？！', '!?', '?!', '.', ':']
  Replace the target sequence set. [], null, or false explicitly disable target matching.
• spaceAfterPunctuationTargetsAdd
  Type: string | string[]
  Default: unset
  Append target sequences after base resolution.
• spaceAfterPunctuationTargetsRemove
  Type: string | string[]
  Default: unset
  Remove sequences from the resolved target list.

Punctuation Spacing Examples

import MarkdownIt from 'markdown-it';
import cjkBreaks from '@peaceroad/markdown-it-cjk-breaks-mod';

const mdHalf = MarkdownIt({ html: true }).use(cjkBreaks, {
  either: true,
  spaceAfterPunctuation: 'half'
});

mdHalf.render('こんにちは！\nWorld');
// <p>こんにちは！ World</p>

const mdFull = MarkdownIt({ html: true }).use(cjkBreaks, {
  either: true,
  spaceAfterPunctuation: 'full'
});

mdFull.render('こんにちは！\nWorld');
// <p>こんにちは！　World</p>

const mdCustom = MarkdownIt({ html: true }).use(cjkBreaks, {
  either: true,
  spaceAfterPunctuation: 'half',
  spaceAfterPunctuationTargets: ['??']
});

mdCustom.render('Hello??\nWorld');
// <p>Hello?? World</p>

Softbreak Normalization Example

import MarkdownIt from 'markdown-it';
import cjkBreaks from '@peaceroad/markdown-it-cjk-breaks-mod';

const md = MarkdownIt({ html: true }).use(cjkBreaks, {
  either: true,
  normalizeSoftBreaks: true
});

md.render('**漢**\nb');
// <p><strong>漢</strong>b</p>

Behavior Notes

• Break suppression follows CSS Text Level 3 style rules used by upstream: ZWSP-adjacent breaks are removed first; otherwise width-class checks are applied with Hangul exclusion.
• Punctuation spacing is never global formatting. It only runs when this plugin actually removes the break.
• The second punctuation pass handles inline markup boundaries (inline code, links/autolinks, images, inline HTML) when a raw newline boundary is verifiably present.
• Matching is fail-closed: if raw boundary reconstruction cannot be proven, no space is inserted.
• If a softbreak is still active between candidate tokens, spacing insertion is skipped.

Compatibility

• Module format: ESM ("type": "module").
• Runtime: works in Node.js ESM environments and browser/VSCode bundling setups that support ESM dependencies.
• Runtime plugin code uses no Node-only APIs (fs, path, etc.); those are confined to tests.
• Plugin installation is first-install-wins: repeated .use(cjkBreaks, newOptions) on the same MarkdownIt instance is ignored. Recreate the instance to change options.
• For plugin chains that rewrite inline text (for example @peaceroad/markdown-it-strong-ja), prefer normalizeSoftBreaks: true for stable behavior.

Upstream And Credits

• Original: markdown-it/markdown-it-cjk-breaks
• Fork enhancement (either): @sup39/markdown-it-cjk-breaks
• Current package: @peaceroad/markdown-it-cjk-breaks-mod

License

• markdown-it/markdown-it-cjk-breaks: MIT
• @sup39/markdown-it-cjk-breaks: MIT
• @peaceroad/markdown-it-cjk-breaks-mod: MIT