Implement inline link serialization that doesn't wrap them in angle (#…

…1171)

brackets

Fixes #1169

packages/remark-mdx/lib/serialize/index.js

@@ -2,6 +2,7 @@
 
 var mdxExpression = require('./mdx-expression')
 var mdxElement = require('./mdx-element')
+var link = require('./link')
 var text = require('./text')
 
 module.exports = serialize
@@ -18,5 +19,6 @@ function serialize(compiler) {
   visitors.mdxBlockExpression = mdxExpression
   visitors.mdxSpanElement = mdxElement
   visitors.mdxBlockElement = mdxElement
+  visitors.link = link
   visitors.text = text
 }

packages/remark-mdx/lib/serialize/link.js

@@ -0,0 +1,65 @@
+'use strict'
+
+// Copied and modified from remark-stringify
+// Original source: https://github.com/remarkjs/remark/blob/19a27c30b13baa3a9e864e528c6a0b901a5fc918/packages/remark-stringify/lib/visitors/link.js
+// License (MIT): https://github.com/remarkjs/remark/blob/main/license
+
+var uri = require('remark-stringify/lib/util/enclose-uri')
+var title = require('remark-stringify/lib/util/enclose-title')
+
+module.exports = link
+
+var space = ' '
+var leftSquareBracket = '['
+var rightSquareBracket = ']'
+var leftParenthesis = '('
+var rightParenthesis = ')'
+
+// Expression for a protocol:
+// See <https://en.wikipedia.org/wiki/Uniform_Resource_Identifier#Generic_syntax>.
+var protocol = /^[a-z][a-z+.-]+:\/?/i
+
+// Stringify a link.
+//
+// With MDX we don't support <https://mdxjs.com> style links, which is the default
+// for remark-stringify (understandably). So, we check for the case where the url
+// and its text are equal. If it is, we serialize/stringify link syntax with the
+// url as the title rather than wrapping it in angle brackets (<>).
+//
+// ```markdown
+// [http://example.com](http://example.com)
+// ```
+//
+// Otherwise, is smart about enclosing `url` (see `encloseURI()`) and `title`
+// (see `encloseTitle()`).
+// ```
+//
+// ```markdown
+// [foo](<foo at bar dot com> 'An "example" e-mail')
+// ```
+//
+// Supports named entities in the `url` and `title` when in `settings.encode`
+// mode.
+function link(node) {
+  var self = this
+  var content = self.encode(node.url || '', node)
+  var exit = self.enterLink()
+  var value = self.all(node).join('')
+
+  exit()
+
+  content = uri(content)
+
+  if (node.title) {
+    content += space + title(self.encode(self.escape(node.title, node), node))
+  }
+
+  return (
+    leftSquareBracket +
+    value +
+    rightSquareBracket +
+    leftParenthesis +
+    content +
+    rightParenthesis
+  )
+}

packages/remark-mdx/test/index.js

@@ -1302,6 +1302,16 @@ test('stringify', function (t) {
     'should serialize an expression attribute (element)'
   )
 
+  t.equal(
+    basic.stringify(
+      u('paragraph', [
+        u('link', {url: 'https://mdxjs.com'}, [u('text', 'https://mdxjs.com')])
+      ])
+    ),
+    '[https://mdxjs.com](https://mdxjs.com)',
+    'should write out a url as the raw value'
+  )
+
   t.equal(
     basic.stringify(
       u('paragraph', [