Use ESM

Author: wooorm

.gitignore

@@ -1,4 +1,3 @@
-.nyc_output/
 coverage/
 node_modules/
 *.log

.prettierignore

@@ -1,3 +1,2 @@
 coverage/
-*.json
 *.md

from-markdown.js

@@ -1,2 +1,31 @@
-exports.fromMarkdown = require('./from-markdown.js')
-exports.toMarkdown = require('./to-markdown.js')
+export const mdxjsEsmFromMarkdown = {
+  enter: {mdxjsEsm: enterMdxjsEsm},
+  exit: {mdxjsEsm: exitMdxjsEsm, mdxjsEsmData: exitMdxjsEsmData}
+}
+
+export const mdxjsEsmToMarkdown = {handlers: {mdxjsEsm: handleMdxjsEsm}}
+
+function enterMdxjsEsm(token) {
+  this.enter({type: 'mdxjsEsm', value: ''}, token)
+  this.buffer() // Capture EOLs
+}
+
+function exitMdxjsEsm(token) {
+  var value = this.resume()
+  var node = this.exit(token)
+
+  node.value = value
+
+  if (token.estree) {
+    node.data = {estree: token.estree}
+  }
+}
+
+function exitMdxjsEsmData(token) {
+  this.config.enter.data.call(this, token)
+  this.config.exit.data.call(this, token)
+}
+
+function handleMdxjsEsm(node) {
+  return node.value || ''
+}

index.js

@@ -28,37 +28,31 @@
   "contributors": [
     "Titus Wormer <tituswormer@gmail.com> (https://wooorm.com)"
   ],
+  "sideEffects": false,
+  "type": "module",
+  "main": "index.js",
   "files": [
-    "from-markdown.js",
-    "index.js",
-    "to-markdown.js"
+    "index.js"
   ],
-  "dependencies": {},
   "devDependencies": {
     "acorn": "^8.0.0",
+    "c8": "^7.0.0",
     "mdast-util-from-markdown": "^0.8.0",
     "mdast-util-to-markdown": "^0.6.0",
     "micromark-extension-mdxjs-esm": "^0.3.0",
-    "nyc": "^15.0.0",
     "prettier": "^2.0.0",
     "remark-cli": "^9.0.0",
     "remark-preset-wooorm": "^8.0.0",
     "tape": "^5.0.0",
-    "unist-util-remove-position": "^3.0.0",
-    "xo": "^0.38.0"
+    "unist-util-remove-position": "^4.0.0",
+    "xo": "^0.39.0"
   },
   "scripts": {
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
-    "test-api": "node test",
-    "test-coverage": "nyc --reporter lcov tape test.js",
+    "test-api": "node --conditions development test.js",
+    "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node --conditions development test.js",
     "test": "npm run format && npm run test-coverage"
   },
-  "nyc": {
-    "check-coverage": true,
-    "lines": 100,
-    "functions": 100,
-    "branches": 100
-  },
   "prettier": {
     "tabWidth": 2,
     "useTabs": false,
@@ -69,7 +63,10 @@
   },
   "xo": {
     "prettier": true,
-    "esnext": false
+    "rules": {
+      "no-var": "off",
+      "prefer-arrow-callback": "off"
+    }
   },
   "remarkConfig": {
     "plugins": [

package.json

@@ -23,6 +23,9 @@ Or use it all through [`remark-mdx`][remark-mdx] (**[remark][]**).
 
 ## Install
 
+This package is [ESM only](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c):
+Node 12+ is needed to use it and it must be `import`ed instead of `require`d.
+
 [npm][]:
 
 ```sh
@@ -122,12 +125,13 @@ d
 
 ## API
 
-### `mdxjsEsm.fromMarkdown`
+This package exports the following identifier: `mdxjsEsmFromMarkdown`,
+`mdxjsEsmToMarkdown`.
+There is no default export.
 
-### `mdxjsEsm.toMarkdown`
+### `mdxjsEsmFromMarkdown`
 
-> Note: the separate extensions are also available at
-> `mdast-util-mdxjs-esm/from-markdown` and `mdast-util-mdxjs-esm/to-markdown`.
+### `mdxjsEsmToMarkdown`
 
 Support MDX.js ESM import/exports.
 The exports are extensions, respectively for

readme.md

@@ -1,16 +1,16 @@
-var test = require('tape')
-var acorn = require('acorn')
-var fromMarkdown = require('mdast-util-from-markdown')
-var toMarkdown = require('mdast-util-to-markdown')
-var removePosition = require('unist-util-remove-position')
-var syntax = require('micromark-extension-mdxjs-esm')
-var mdxjsEsm = require('.')
+import test from 'tape'
+import * as acorn from 'acorn'
+import fromMarkdown from 'mdast-util-from-markdown'
+import toMarkdown from 'mdast-util-to-markdown'
+import {removePosition} from 'unist-util-remove-position'
+import mdxjsEsm from 'micromark-extension-mdxjs-esm'
+import {mdxjsEsmFromMarkdown, mdxjsEsmToMarkdown} from './index.js'
 
 test('markdown -> mdast', function (t) {
   t.deepEqual(
     fromMarkdown('import a from "b"\nexport var c = ""\n\nd', {
-      extensions: [syntax({acorn: acorn})],
-      mdastExtensions: [mdxjsEsm.fromMarkdown]
+      extensions: [mdxjsEsm({acorn})],
+      mdastExtensions: [mdxjsEsmFromMarkdown]
     }),
     {
       type: 'root',
@@ -55,8 +55,8 @@ test('markdown -> mdast', function (t) {
       JSON.stringify(
         removePosition(
           fromMarkdown('import a from "b"\nexport var c = ""\n\nd', {
-            extensions: [syntax({acorn: acorn, addResult: true})],
-            mdastExtensions: [mdxjsEsm.fromMarkdown]
+            extensions: [mdxjsEsm({acorn, addResult: true})],
+            mdastExtensions: [mdxjsEsmFromMarkdown]
           }),
           true
         )
@@ -188,7 +188,7 @@ test('markdown -> mdast', function (t) {
         {type: 'paragraph', children: [{type: 'text', value: 'd'}]}
       ]
     },
-    'should add a `data.estree` if `addResult` was used in the syntax plugin'
+    'should add a `data.estree` if `addResult` was used in the syntax extension'
   )
 
   t.end()
@@ -204,7 +204,7 @@ test('mdast -> markdown', function (t) {
           {type: 'paragraph', children: [{type: 'text', value: 'd'}]}
         ]
       },
-      {extensions: [mdxjsEsm.toMarkdown]}
+      {extensions: [mdxjsEsmToMarkdown]}
     ),
     'import a from "b"\nexport var c = ""\n\nd\n',
     'should serialize ESM'
@@ -219,7 +219,7 @@ test('mdast -> markdown', function (t) {
           {type: 'paragraph', children: [{type: 'text', value: 'd'}]}
         ]
       },
-      {extensions: [mdxjsEsm.toMarkdown]}
+      {extensions: [mdxjsEsmToMarkdown]}
     ),
     '\n\nd\n',
     'should not crash on ESM missing `value`'