Add MDX support

Closes GH-270.
Closes GH-271.

cli.js

@@ -9,6 +9,7 @@ var unified = require('unified')
 var markdown = require('remark-parse')
 var html = require('rehype-parse')
 var frontmatter = require('remark-frontmatter')
+var mdx = require('remark-mdx')
 var english = require('retext-english')
 var remark2retext = require('remark-retext')
 var rehype2retext = require('rehype-retext')
@@ -30,6 +31,7 @@ var textExtensions = [
   'ron'
 ]
 var htmlExtensions = ['htm', 'html']
+var mdxExtensions = ['mdx']
 
 // Update messages.
 notifier({pkg: pack}).notify()
@@ -45,6 +47,7 @@ var cli = meow(
     '  -q, --quiet  output only warnings and errors',
     '  -t, --text   treat input as plain-text (not markdown)',
     '  -l, --html   treat input as html (not markdown)',
+    '      --mdx    treat input as mdx (not markdown)',
     '  -d, --diff   ignore unchanged lines (affects Travis only)',
     '  --stdin      read from stdin',
     '',
@@ -62,6 +65,7 @@ var cli = meow(
       help: {type: 'boolean', alias: 'h'},
       stdin: {type: 'boolean'},
       text: {type: 'boolean', alias: 't'},
+      mdx: {type: 'boolean'},
       html: {type: 'boolean', alias: 'l'},
       diff: {type: 'boolean', alias: 'd'},
       quiet: {type: 'boolean', alias: 'q'},
@@ -71,7 +75,11 @@ var cli = meow(
 )
 
 // Set-up.
-var extensions = cli.flags.html ? htmlExtensions : textExtensions
+var extensions = cli.flags.html
+  ? htmlExtensions
+  : cli.flags.mdx
+  ? mdxExtensions
+  : textExtensions
 var defaultGlobs = ['{docs/**/,doc/**/,}*.{' + extensions.join(',') + '}']
 var silentlyIgnore
 var globs
@@ -127,6 +135,12 @@ function transform(options) {
 
   if (cli.flags.html) {
     plugins = [html, [rehype2retext, unified().use({plugins: plugins})]]
+  } else if (cli.flags.mdx) {
+    plugins = [
+      markdown,
+      mdx,
+      [remark2retext, unified().use({plugins: plugins})]
+    ]
   } else if (!cli.flags.text) {
     plugins = [
       markdown,

index.js

@@ -4,6 +4,7 @@ var VFile = require('vfile')
 var unified = require('unified')
 var markdown = require('remark-parse')
 var frontmatter = require('remark-frontmatter')
+var mdx = require('remark-mdx')
 var html = require('rehype-parse')
 var english = require('retext-english')
 var equality = require('retext-equality')
@@ -16,6 +17,7 @@ var filter = require('./filter')
 module.exports = alex
 alex.text = noMarkdown
 alex.markdown = alex
+alex.mdx = mdxParse
 alex.html = htmlParse
 
 function makeText(config) {
@@ -63,6 +65,15 @@ function alex(value, config) {
   )
 }
 
+// Alex, for MDX.
+function mdxParse(value, config) {
+  return core(
+    value,
+    config,
+    unified().use(markdown).use(mdx).use(remark2retext, makeText(config))
+  )
+}
+
 // Alex, for HTML.
 function htmlParse(value, config) {
   return core(

package.json

@@ -60,6 +60,7 @@
     "rehype-parse": "^7.0.0",
     "rehype-retext": "^2.0.1",
     "remark-frontmatter": "^2.0.0",
+    "remark-mdx": "^2.0.0-next.7",
     "remark-message-control": "^6.0.0",
     "remark-parse": "^8.0.0",
     "remark-retext": "^4.0.0",

readme.md

@@ -26,7 +26,7 @@ Give **alex** a spin on the [Online demo »][demo].
 *   [x] Helps to get better at considerate writing
 *   [x] Catches many possible offences
 *   [x] Suggests helpful alternatives
-*   [x] Reads plain text, HTML, and markdown as input
+*   [x] Reads plain text, HTML, MDX, or markdown as input
 *   [x] Stylish
 
 ## Install
@@ -60,6 +60,7 @@ Or you can follow this step-by-step tutorial:
 *   [API](#api)
     *   [`alex(value, config)`](#alexvalue-config)
     *   [`alex.markdown(value, config)`](#alexmarkdownvalue-config)
+    *   [`alex.mdx(value, config)`](#alexmdxvalue-config)
     *   [`alex.html(value, config)`](#alexhtmlvalue-config)
     *   [`alex.text(value, config)`](#alextextvalue-config)
 *   [Workflow](#workflow)
@@ -107,7 +108,7 @@ like][literals] are not warned about.
 *   Ember — [`yohanmishkin/ember-cli-alex`](https://github.com/yohanmishkin/ember-cli-alex)
 *   Probot — [`swinton/linter-alex`](https://github.com/swinton/linter-alex)
 *   GitHub Actions — [`brown-ccv/alex-recommends`](https://github.com/marketplace/actions/alex-recommends)
-*   GitHub Actions (reviewdog) — [`reviewdog/action-alex`](https://github.com/marketplace/actions/run-alex-with-reviewdog) 
+*   GitHub Actions (reviewdog) — [`reviewdog/action-alex`](https://github.com/marketplace/actions/run-alex-with-reviewdog)
 *   Vim — [`w0rp/ale`](https://github.com/w0rp/ale)
 *   Browser extension — [`skn0tt/alex-browser-extension`](https://github.com/skn0tt/alex-browser-extension)
 *   Contentful - [`stefanjudis/alex-js-contentful-ui-extension`](https://github.com/stefanjudis/alex-js-contentful-ui-extension)
@@ -309,6 +310,7 @@ See `$ alex --help` for more information.
 
 > When no input files are given to **alex**, it searches for files in the
 > current directory, `doc`, and `docs`.
+> If `--mdx` is given, it searches for `mdx` extensions.
 > If `--html` is given, it searches for `htm` and `html` extensions.
 > Otherwise, it searches for `txt`, `text`, `md`, `mkd`, `mkdn`, `mkdown`,
 > `ron`, and `markdown` extensions.
@@ -369,6 +371,46 @@ Yields:
 ]
 ```
 
+### `alex.mdx(value, config)`
+
+Check [MDX][] (ignoring syntax).
+
+> Note: the syntax for [MDX@2][mdx-next], while currently in beta, is used in
+> alex.
+
+###### Parameters
+
+*   `value` ([`VFile`][vfile] or `string`) — MDX document
+*   `config` (`Object`, optional) — See the [Configuration][] section
+
+###### Returns
+
+[`VFile`][vfile].
+
+###### Example
+
+```js
+alex.mdx('<Component>He walked to class.</Component>').messages
+```
+
+Yields:
+
+```js
+[
+  [1:12-1:14: `He` may be insensitive, use `They`, `It` instead] {
+    reason: '`He` may be insensitive, use `They`, `It` instead',
+    line: 1,
+    column: 12,
+    location: { start: [Object], end: [Object] },
+    source: 'retext-equality',
+    ruleId: 'he-she',
+    fatal: false,
+    actual: 'He',
+    expected: [ 'They', 'It' ]
+  }
+]
+```
+
 ### `alex.html(value, config)`
 
 Check HTML (ignoring syntax).
@@ -635,3 +677,7 @@ Lots of [people helped since][contributors]!
 [ignoring-files]: #ignoring-files
 
 [alexignore]: #alexignore
+
+[mdx]: https://mdxjs.com
+
+[mdx-next]: https://github.com/mdx-js/mdx/issues/1041

test/api.js

@@ -6,6 +6,7 @@ var test = require('tape')
 var alex = require('..')
 
 var html = fs.readFileSync(path.join(__dirname, 'fixtures', 'three.html'))
+var mdx = fs.readFileSync(path.join(__dirname, 'fixtures', 'four.mdx'))
 
 // Tests. Note that these are small because alex is in fact
 // just a collection of well-tested modules.
@@ -318,5 +319,24 @@ test('alex()', function (t) {
     'alex.html() with deny and profanity config'
   )
 
+  t.deepEqual(
+    alex.mdx(mdx).messages.map(String),
+    [
+      '3:1-3:4: `She` may be insensitive, use `They`, `It` instead',
+      '3:32-3:38: Don’t use `asshat`, it’s profane',
+      '3:70-3:74: Be careful with `butt`, it’s profane in some cases'
+    ],
+    'alex.mdx()'
+  )
+
+  t.deepEqual(
+    alex.mdx(mdx, ['butt']).messages.map(String),
+    [
+      '3:1-3:4: `She` may be insensitive, use `They`, `It` instead',
+      '3:32-3:38: Don’t use `asshat`, it’s profane'
+    ],
+    'alex.mdx() with options'
+  )
+
   t.end()
 })

test/cli.js

@@ -145,6 +145,22 @@ test('alex-cli', function (t) {
     }
   })
 
+  t.test('mdx', function (t) {
+    var fp = path.join('test', 'fixtures')
+
+    t.plan(1)
+
+    childProcess.exec('./cli.js ' + fp + ' --mdx', onexec)
+
+    function onexec(err, stdout, stderr) {
+      t.deepEqual(
+        [err.code, /2 warnings/.test(stderr), stdout],
+        [1, true, ''],
+        'should work'
+      )
+    }
+  })
+
   t.test('successful', function (t) {
     var fp = path.join('test', 'fixtures', 'ok.txt')
 

test/fixtures/four.mdx

@@ -0,0 +1,4 @@
+<Component disabled>We’ve confirmed `his` identity.</Component>
+
+She walked to class. Eric, the asshat, is pretty set on beating your butt
+for the sheriff.