remark-lint-no-tabs

remark-lint-no-tabs

remark-lint rule to warn when tabs are used.

Contents

• What is this?
• When should I use this?
• Presets
• Install
• Use
• API
  • unified().use(remarkLintNoTabs)
• Recommendation
• Fix
• Examples
• Compatibility
• Contribute
• License

What is this?

This package checks for tabs.

When should I use this?

You can use this package to check tabs.

Presets

This plugin is not included in presets maintained here.

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install remark-lint-no-tabs

In Deno with esm.sh:

import remarkLintNoTabs from 'https://esm.sh/remark-lint-no-tabs@4'

In browsers with esm.sh:

<script type="module">
  import remarkLintNoTabs from 'https://esm.sh/remark-lint-no-tabs@4?bundle'
</script>

Use

On the API:

import remarkLint from 'remark-lint'
import remarkLintNoTabs from 'remark-lint-no-tabs'
import remarkParse from 'remark-parse'
import remarkStringify from 'remark-stringify'
import {read} from 'to-vfile'
import {unified} from 'unified'
import {reporter} from 'vfile-reporter'

const file = await read('example.md')

await unified()
  .use(remarkParse)
  .use(remarkLint)
  .use(remarkLintNoTabs)
  .use(remarkStringify)
  .process(file)

console.error(reporter(file))

On the CLI:

remark --frail --use remark-lint --use remark-lint-no-tabs .

On the CLI in a config file (here a package.json):

 …
 "remarkConfig": {
   "plugins": [
     …
     "remark-lint",
+    "remark-lint-no-tabs",
     …
   ]
 }
 …

API

This package exports no identifiers. It exports no additional TypeScript types. The default export is remarkLintNoTabs.

unified().use(remarkLintNoTabs)

Warn when tabs are used.

Parameters

There are no options.

Returns

Transform (Transformer from unified).

Recommendation

Regardless of the debate in other languages of whether to use tabs versus spaces, when it comes to markdown, tabs do not work as expected. Largely around things such as block quotes, lists, and indented code.

Take for example block quotes: >\ta gives a paragraph with the text a in a blockquote, so one might expect that >\t\ta results in indented code with the text a in a block quote.

>\ta

>\t\ta

Yields:

<blockquote>
<p>a</p>
</blockquote>
<blockquote>
<pre><code>  a
</code></pre>
</blockquote>

Because markdown uses a hardcoded tab size of 4, the first tab could be represented as 3 spaces (because there’s a > before). One of those “spaces” is taken because block quotes allow the > to be followed by one space, leaving 2 spaces. The next tab can be represented as 4 spaces, so together we have 6 spaces. The indented code uses 4 spaces, so there are two spaces left, which are shown in the indented code.

Fix

remark-stringify uses spaces exclusively for indentation.

Examples

ok.md

In

␠␠␠␠mercury()

Out

No messages.

not-ok.md

In

␉mercury()

Venus␉and Earth.

Out

1:1: Unexpected tab (`\t`), expected spaces
3:6: Unexpected tab (`\t`), expected spaces

Compatibility

Projects maintained by the unified collective are compatible with maintained versions of Node.js.

When we cut a new major release, we drop support for unmaintained versions of Node. This means we try to keep the current release line, remark-lint-no-tabs@4, compatible with Node.js 16.

Contribute

See contributing.md in remarkjs/.github for ways to get started. See support.md for ways to get help.

This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.

License

MIT © Titus Wormer