fuxi-fmt

A Markdown formatter for Chinese technical writing.

VS Code runs exactly one formatter per language per save, so formatters cannot be composed. Prettier owns block structure but inserts spaces between CJK and Latin and knows nothing about Chinese punctuation. AutoCorrect owns CJK punctuation but is not a formatting provider and can never hold editor.defaultFormatter. fuxi-fmt is one engine that owns both halves.

What it does


Blank lines	Around blocks: exactly one, or at least one. Never inside a list or blockquote unless you ask.
Markers	One space after `#`, and after every `-`, `*`, `+` and `1.` marker.
Ordered lists	Renumbered from the declared start, with markers and indentation normalised.
Inline code	Treated as an English word, so `code` is spaced when it meets Chinese.
CJK to Latin	A space at the boundary only. `GPT-4o`, `60公里/小时` and `2.5` are left alone.
Punctuation width	Decided by what sits next to it, which is why `1,000` and `e.g.` stay half-width.

Code is never touched

Fenced code bodies, fence indentation and info strings, front matter, inline code and math, HTML blocks and comments, MDX and JSX, shortcodes, wikilinks, URLs and link destinations are all byte-verbatim. A rule that touched one of these would be a bug, not a rounding error.

It never wraps

Chinese has no spaces to break at, so a wrapping printer has to split between characters. fuxi-fmt never joins, splits or reflows a line.

Install

Search the Marketplace for fuxi-fmt, or:

code --install-extension Fux-i.fuxi-fmt-vscode

Configure

A fuxi-fmt.json at the workspace root configures the project. Editor settings override it, so a personal preference does not require editing a committed file:

{
  "fuxiFmt.enable": true,
  "fuxiFmt.config": { "blankLines": { "aroundBlocks": "atLeast" } }
}

Set fuxiFmt.enable to false to turn the formatter off without uninstalling it.

When it is wrong about your document

Every rule can be wrong for one paragraph. Three directives say so, and nothing inside them is touched:

<!-- fuxi-fmt-ignore-file -->

<!-- fuxi-fmt-ignore-start -->
这 一段 保持 原样
<!-- fuxi-fmt-ignore-end -->

<!-- fuxi-fmt-ignore -->
这一块保持原样

Guarantees

Minimal edits. A change produces a small edit range, so format-on-save does not rewrite the file and does not disturb the cursor or the undo history.
Semantic preservation. A guard compares the result against the input and refuses to return a document that parses differently. If it fires, you get your document back unchanged.
Idempotent. Running it twice changes nothing the second time.
No dependencies. The engine has no runtime dependencies and never imports the VS Code API.

License

MIT

fuxi-fmt

Fux-i

fuxi-fmt

What it does

Code is never touched

It never wraps

Install

Configure

When it is wrong about your document

Guarantees

Links

License