CJK-friendly emphasis

Ensures bold and italic markers adjacent to CJK ideographs and kana are interpreted correctly.

CjkFriendlyPlugin is always active. It post-processes the parsed markdown AST and re-tokenises emphasis flanking rules for CJK content.

Why this exists

CommonMark’s emphasis flanking rules treat CJK ideographs and kana as non-whitespace non-punctuation. This means a ** adjacent to CJK text — such as **テスト。**テスト — is not considered right-flanking by the base parser, and renders as literal stars instead of <strong>.

CjkFriendlyPlugin post-processes the parsed markdown AST and re-tokenises these cases. The result matches the intuitive expectation for Japanese, Chinese, and Korean content sites.

Behaviour

Default: always on. No configuration key required.

Opt-out (rare): set cjkFriendly: false in zfb.config.ts only when you need strict CommonMark output and your content has no CJK emphasis:

import { defineConfig } from "zfb/config";

export default defineConfig({
  markdown: {
    cjkFriendly: false,
  },
});

Scope

This plugin handles **bold** and _italic_ adjacent to CJK characters. GFM strikethrough (~~foo~~) does not need the toggle — markdown-rs’s GFM tokeniser handles ~~ delimiter runs independently, so strikethrough works correctly at CJK boundaries in both modes.

See also

• Customizing Markdown — full pipeline overview.