Add options.tightSelfClosing for space before slash

Related to: GH-3.

Author: wooorm

lib/index.js

@@ -22,6 +22,9 @@
  *   Preferred quote to use around attribute values.
  * @property {boolean} [quoteSmart=false]
  *   Use the other quote if that results in less bytes.
+ * @property {boolean} [tightSelfClosing=true]
+ *   Do not use an extra space when closing self-closing elements: `<img/>`
+ *   instead of `<img />`.
  */
 
 import {ccount} from 'ccount'
@@ -363,7 +366,7 @@ export function mdxJsxFromMarkdown() {
  * @returns {ToMarkdownExtension}
  */
 export function mdxJsxToMarkdown(options = {}) {
-  const {quote = '"', quoteSmart} = options
+  const {quote = '"', quoteSmart, tightSelfClosing = true} = options
   const alternative = quote === '"' ? "'" : '"'
 
   if (quote !== '"' && quote !== "'") {
@@ -458,7 +461,9 @@ export function mdxJsxToMarkdown(options = {}) {
       '<' +
       (node.name || '') +
       attributeValue +
-      (selfClosing ? '/' : '') +
+      (selfClosing
+        ? (tightSelfClosing || /[ \n]$/.test(attributeValue) ? '' : ' ') + '/'
+        : '') +
       '>' +
       (node.children && node.children.length > 0
         ? node.type === 'mdxJsxFlowElement'

readme.md

@@ -242,6 +242,11 @@ Preferred quote to use around attribute values (`'"'` or `"'"`, default: `'"'`).
 
 Use the other quote if that results in less bytes (`boolean`, default: `false`).
 
+###### `options.tightSelfClosing`
+
+Do not use an extra space when closing self-closing elements: `<img/>` instead
+of `<img />` (`boolean`, default: `true`).
+
 ## Syntax tree
 
 The following interfaces are added to **[mdast][]** by this utility.

test.js

@@ -1923,5 +1923,23 @@ test('mdast -> markdown', (t) => {
     'should support `options.quoteSmart`: use quote w/ more alternative quotes'
   )
 
+  t.deepEqual(
+    toMarkdown(
+      {type: 'mdxJsxFlowElement', name: 'x', attributes: [], children: []},
+      {extensions: [mdxJsxToMarkdown({tightSelfClosing: false})]}
+    ),
+    '<x />\n',
+    'should support `options.tightSelfClosing`: no space when `false`'
+  )
+
+  t.deepEqual(
+    toMarkdown(
+      {type: 'mdxJsxFlowElement', name: 'x', attributes: [], children: []},
+      {extensions: [mdxJsxToMarkdown({tightSelfClosing: true})]}
+    ),
+    '<x/>\n',
+    'should support `options.tightSelfClosing`: space when `true`'
+  )
+
   t.end()
 })