Add singleDollarTextMath option

This option can be used to prevent math (text) from forming if only one
dollar is used.

Closes GH-63.

packages/remark-math/index.js

@@ -1,5 +1,6 @@
 /**
  * @typedef {import('mdast').Root} Root
+ * @typedef {import('mdast-util-math').ToOptions} Options
  *
  * @typedef {import('mdast-util-math')} DoNotTouchAsThisImportIncludesMathInTree
  */
@@ -10,14 +11,14 @@ import {mathFromMarkdown, mathToMarkdown} from 'mdast-util-math'
 /**
  * Plugin to support math.
  *
- * @type {import('unified').Plugin<void[], Root>}
+ * @type {import('unified').Plugin<[Options?] | void[], Root, Root>}
  */
-export default function remarkMath() {
+export default function remarkMath(options = {}) {
   const data = this.data()
 
-  add('micromarkExtensions', math)
-  add('fromMarkdownExtensions', mathFromMarkdown)
-  add('toMarkdownExtensions', mathToMarkdown)
+  add('micromarkExtensions', math(options))
+  add('fromMarkdownExtensions', mathFromMarkdown())
+  add('toMarkdownExtensions', mathToMarkdown(options))
 
   /**
    * @param {string} field

packages/remark-math/package.json

@@ -36,8 +36,8 @@
   ],
   "dependencies": {
     "@types/mdast": "^3.0.0",
-    "mdast-util-math": "^1.0.0",
-    "micromark-extension-math": "^1.0.0",
+    "mdast-util-math": "^2.0.0",
+    "micromark-extension-math": "^2.0.0",
     "unified": "^10.0.0"
   },
   "scripts": {

packages/remark-math/readme.md

@@ -88,6 +88,15 @@ Get’s useful when combined with [`rehype-katex`][rehype-katex] or
 See [`micromark/micromark-extension-math`][extension-math] for more info on what
 syntax is supported.
 
+##### `options`
+
+###### `options.singleDollarTextMath`
+
+Whether to support math (text) with a single dollar (`boolean`, default:
+`true`).
+Single dollars work in Pandoc and many other places, but often interfere with
+“normal” dollars in text.
+
 #### Notes
 
 ##### Escaping

packages/remark-math/test.js

@@ -318,6 +318,29 @@ test('remarkMath', (t) => {
     'should stringify inline and block math'
   )
 
+  t.deepEqual(
+    unified()
+      .use(remarkParse)
+      .use(remarkStringify)
+      .use(remarkMath, {singleDollarTextMath: false})
+      .processSync('Math $\\alpha$\n\n$$\\beta+\\gamma$$\n')
+      .toString(),
+    'Math $\\alpha$\n\n$$\\beta+\\gamma$$\n',
+    'should support `singleDollarTextMath: false` (1)'
+  )
+
+  t.deepEqual(
+    unified()
+      .use(remarkParse)
+      .use(remarkMath, {singleDollarTextMath: false})
+      .use(remarkRehype)
+      .use(rehypeStringify)
+      .processSync('Math $\\alpha$\n\n$$\\beta+\\gamma$$\n')
+      .toString(),
+    '<p>Math $\\alpha$</p>\n<p><span class="math math-inline">\\beta+\\gamma</span></p>',
+    'should support `singleDollarTextMath: false` (2)'
+  )
+
   t.deepEqual(
     unified()
       .use(remarkParse)

readme.md

@@ -80,7 +80,7 @@ But in a browser, that looks something like this:
 
 ## Packages
 
-This repo houses four packages:
+This repo houses three packages:
 
 *   [`remark-math`][remark-math]
     — Parses `$` as `inlineMath` and `$$` as `math` nodes