code

comark-code

Copy and Wrap buttons on every Markdown code block, plus buttons of your own, such as Run, that hand the block's code to your app. Without a script the block shows as it would without the plugin. A Comark plugin for HTML, Vue, React, and Svelte.

pnpm add comark comark-code

import { createHtmlRenderer } from "@comark/html";
import code, { components } from "comark-code/html";

const render = createHtmlRenderer({ plugins: [code()], components });

The components replace how pre renders, and keep the block's own markup inside a wrapper, so Shiki's highlighting and your pre styles still apply. Each block gets a header above its first line, with the file's name or the language and the buttons, so they never cover the code. They work in a comark-tabs code group whichever plugin comes first.

Copy writes the code to the clipboard and shows a check. When the page can't write to it, such as over plain http, it selects the code and says to press Ctrl+C or ⌘C. Wrap breaks long lines in that block until it's pressed again.

Lines

Words after the fence's language, written the way Expressive Code writes them, mark lines, fold them, and frame the block:

```ts title="src/zoom.ts" del={3} ins={4} mark={1} showLineNumbers
function close() {
  dialog.close();
  history.back();
  if (opened) history.back();
}
```

ins, del, and mark tint lines green, red, or gray; collapse folds a range into a <details>; showLineNumbers and startLineNumber=120 number the lines; title names the block like [file]; wrap starts it wrapped. Shell blocks are drawn as a terminal, and frame="none" turns that off. A ```diff lang="ts" fence takes pasted git diff output, highlights it as TypeScript, and marks its + and - lines. Comark's Shiki plugin redraws every block, so list shiki() before code(). A range the plugin can't read goes in meta.issues.

Actions

Each action is a button on the code blocks in its languages, or on every block without them. It shows a label, an Iconify icon, or both; an icon-only button needs a title:

const render = createHtmlRenderer({
  plugins: [
    code({
      actions: [
        { id: "run", label: "Run", icon: "lucide:play", languages: ["sh", "bash"] },
        { id: "explain", icon: "lucide:sparkles", title: "Explain this code" },
      ],
    }),
  ],
  components,
});

Your app decides what an action does, in the page:

import { onCodeAction } from "comark-code/client";

const stop = onCodeAction("run", ({ code, language }) => terminal.run(code));

A click sends a comark-code-action event from the block that bubbles up to the page; onCodeAction() listens for one action's.

Renderers

Renderer	Import
@comark/html	comark-code/html: the styles and script are inlined once per document
@comark/vue	comark-code/vue
@comark/react	comark-code/react
@comark/svelte	comark-code/svelte, Svelte 5.20 or later

Each entry exports the parse plugin as default and the renderer's components.

The buttons read shadcn's CSS variables, such as --background and --border, when the page has them, and use its neutral theme otherwise. Set the --comark-* tokens to theme every comark plugin at once. The rules sit in a comark CSS layer, so any plain rule of your own wins, except the two that make room for the header and wrap lines. --ck-inset sets how far the buttons sit from the corner and --ck-button-size sizes them, and the header grows to fit. --ck-title-font sets the title's font; see the code's Theming page.