## Usage
### Installing
Install the plugin alongside ESLint v9.15.0 or greater.
For Node.js and compatible runtimes:
```sh
npm install @eslint/markdown -D
# or
yarn add @eslint/markdown -D
# or
pnpm install @eslint/markdown -D
# or
bun add @eslint/markdown -D
```
For Deno:
```sh
deno add jsr:@eslint/markdown
```
### Configurations
| **Configuration Name** | **Description** |
| ---------------------- | ---------------------------------------------------------------------------------------------------------- |
| `recommended` | Lints all `.md` files with the recommended rules and assumes [CommonMark](https://commonmark.org/) format. |
| `processor` | Enables extracting code blocks from all `.md` files so code blocks can be individually linted. |
In your `eslint.config.js` file, import `@eslint/markdown` and include the recommended config to enable Markdown parsing and linting:
```js
// eslint.config.js
import { defineConfig } from "eslint/config";
import markdown from "@eslint/markdown";
export default defineConfig([
{
files: ["**/*.md"],
plugins: {
markdown,
},
extends: ["markdown/recommended"],
},
// your other configs here
]);
```
You can also modify the recommended config by using `extends`:
```js
// eslint.config.js
import { defineConfig } from "eslint/config";
import markdown from "@eslint/markdown";
export default defineConfig([
{
plugins: {
markdown,
},
extends: ["markdown/recommended"],
rules: {
"markdown/no-html": "error",
},
},
// your other configs here
]);
```
### Rules
| **Rule Name** | **Description** | **Recommended** |
| :----------------------------------------------------------------------------- | :------------------------------------------------------------------------------------------------ | :-------------: |
| [`fenced-code-language`](./docs/rules/fenced-code-language.md) | Require languages for fenced code blocks | yes |
| [`fenced-code-meta`](./docs/rules/fenced-code-meta.md) | Require or disallow metadata for fenced code blocks | no |
| [`heading-increment`](./docs/rules/heading-increment.md) | Enforce heading levels increment by one | yes |
| [`no-bare-urls`](./docs/rules/no-bare-urls.md) | Disallow bare URLs | no |
| [`no-duplicate-definitions`](./docs/rules/no-duplicate-definitions.md) | Disallow duplicate definitions | yes |
| [`no-duplicate-headings`](./docs/rules/no-duplicate-headings.md) | Disallow duplicate headings in the same document | no |
| [`no-empty-definitions`](./docs/rules/no-empty-definitions.md) | Disallow empty definitions | yes |
| [`no-empty-images`](./docs/rules/no-empty-images.md) | Disallow empty images | yes |
| [`no-empty-links`](./docs/rules/no-empty-links.md) | Disallow empty links | yes |
| [`no-html`](./docs/rules/no-html.md) | Disallow HTML tags | no |
| [`no-invalid-label-refs`](./docs/rules/no-invalid-label-refs.md) | Disallow invalid label references | yes |
| [`no-missing-atx-heading-space`](./docs/rules/no-missing-atx-heading-space.md) | Disallow headings without a space after the hash characters | yes |
| [`no-missing-label-refs`](./docs/rules/no-missing-label-refs.md) | Disallow missing label references | yes |
| [`no-missing-link-fragments`](./docs/rules/no-missing-link-fragments.md) | Disallow link fragments that do not reference valid headings | yes |
| [`no-multiple-h1`](./docs/rules/no-multiple-h1.md) | Disallow multiple H1 headings in the same document | yes |
| [`no-reference-like-urls`](./docs/rules/no-reference-like-urls.md) | Disallow URLs that match defined reference identifiers | yes |
| [`no-reversed-media-syntax`](./docs/rules/no-reversed-media-syntax.md) | Disallow reversed link and image syntax | yes |
| [`no-space-in-emphasis`](./docs/rules/no-space-in-emphasis.md) | Disallow spaces around emphasis markers | yes |
| [`no-unused-definitions`](./docs/rules/no-unused-definitions.md) | Disallow unused definitions | yes |
| [`require-alt-text`](./docs/rules/require-alt-text.md) | Require alternative text for images | yes |
| [`table-column-count`](./docs/rules/table-column-count.md) | Disallow data rows in a GitHub Flavored Markdown table from having more cells than the header row | yes |
**Note:** This plugin does not provide formatting rules. We recommend using a source code formatter such as [Prettier](https://prettier.io) for that purpose.
In order to individually configure a rule in your `eslint.config.js` file, import `@eslint/markdown` and configure each rule with a prefix:
```js
// eslint.config.js
import { defineConfig } from "eslint/config";
import markdown from "@eslint/markdown";
export default defineConfig([
{
files: ["**/*.md"],
plugins: {
markdown,
},
language: "markdown/commonmark",
rules: {
"markdown/no-html": "error",
},
},
]);
```
You can individually disable rules in Markdown using HTML comments, such as:
```markdown
