markdown/no-missing-atx-heading-space

#Install is not a heading. Without a space after the #, Markdown reads the line as a paragraph that starts with a hash.

--fix adds the space.

Configure

Off by default. It needs an ESLint config that says which files are in the language:

import markdown from "@eslint/markdown";

export default [
  {
    files: ["**/*.md"],
    plugins: { markdown },
    language: "markdown/commonmark",
    rules: { "markdown/no-missing-atx-heading-space": "error" },
  },
];

It also works with markdown/gfm.

Examples

Reported:

#Install

##With Homebrew

Not reported:

# Install

## With Homebrew

Issue \#12 and #12 in the middle of a line are fine.

Options

Option	Default	What it does
checkClosedHeadings	false	Also require a space before the # characters that close a heading.

Without that space the closing # characters are part of the heading's text:

# Install#

# Install #