Use remark-mdx in core as a syntactic extension to remark

packages/mdx/index.js

@@ -1,65 +1,26 @@
 const unified = require('unified')
 const toMDAST = require('remark-parse')
+const remarkMdx = require('remark-mdx')
 const squeeze = require('remark-squeeze-paragraphs')
 const visit = require('unist-util-visit')
 const raw = require('hast-util-raw')
 const toMDXAST = require('./md-ast-to-mdx-ast')
 const mdxAstToMdxHast = require('./mdx-ast-to-mdx-hast')
 const mdxHastToJsx = require('./mdx-hast-to-jsx')
 
-const {
-  isImport,
-  isExport,
-  isExportDefault,
-  BLOCKS_REGEX,
-  EMPTY_NEWLINE
-} = require('./util')
-
 const DEFAULT_OPTIONS = {
   footnotes: true,
   mdPlugins: [],
   hastPlugins: [],
-  compilers: [],
-  blocks: [BLOCKS_REGEX]
-}
-
-const tokenizeEsSyntax = (eat, value) => {
-  const index = value.indexOf(EMPTY_NEWLINE)
-  const subvalue = index !== -1 ? value.slice(0, index) : value
-
-  if (isExport(subvalue)) {
-    return eat(subvalue)({
-      type: 'export',
-      default: isExportDefault(subvalue),
-      value: subvalue
-    })
-  }
-
-  if (isImport(subvalue)) {
-    return eat(subvalue)({type: 'import', value: subvalue})
-  }
-}
-
-tokenizeEsSyntax.locator = (value, _fromIndex) => {
-  return isExport(value) || isImport(value) ? -1 : 1
-}
-
-function esSyntax() {
-  const Parser = this.Parser
-  const tokenizers = Parser.prototype.blockTokenizers
-  const methods = Parser.prototype.blockMethods
-
-  tokenizers.esSyntax = tokenizeEsSyntax
-
-  methods.splice(methods.indexOf('paragraph'), 0, 'esSyntax')
+  compilers: []
 }
 
 function createMdxAstCompiler(options) {
   const mdPlugins = options.mdPlugins
 
   const fn = unified()
     .use(toMDAST, options)
-    .use(esSyntax)
+    .use(remarkMdx, options)
     .use(squeeze, options)
     .use(toMDXAST, options)
 

packages/mdx/license

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2017-2018 Compositor and Zeit, Inc.
+Copyright (c) 2017-2019 Compositor, Inc. and Zeit, Inc.
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

packages/mdx/md-ast-to-mdx-ast.js

@@ -4,15 +4,13 @@ const commentOpen = '<!--'
 const commentClose = '-->'
 
 module.exports = _options => tree => {
-  visit(tree, 'html', node => {
+  visit(tree, 'jsx', node => {
     if (
       node.value.startsWith(commentOpen) &&
       node.value.endsWith(commentClose)
     ) {
       node.type = 'comment'
       node.value = node.value.slice(commentOpen.length, -commentClose.length)
-    } else {
-      node.type = node.mdxType || 'jsx'
     }
   })
 

packages/mdx/mdx-hast-to-jsx.js

@@ -49,47 +49,6 @@ function toJSX(node, parentNode = {}, options = {}) {
           continue
         }
 
-        if (
-          /^export\s{\s?default\s?}\sfrom/.test(childNode.value) ||
-          /^export\s{.*?as\sdefault\s?}/.test(childNode.value)
-        ) {
-          let example
-
-          // eslint-disable-next-line max-depth
-          if (/\}\s*from\s+/.test(childNode.value)) {
-            example = `
-              For example, instead of:
-
-              export { default } from './Layout'
-
-              use:
-
-              import Layout from './Layout'
-              export default Layout
-            `.trim()
-          } else {
-            example = `
-              For example, instead of:
-
-              export { Layout as default }
-
-              use:
-
-              export default Layout
-            `.trim()
-          }
-
-          throw new Error(
-            `
-            MDX doesn't support using "default" as a named export, use "export default" statement instead.
-
-            ${example}
-          `
-              .trim()
-              .replace(/^ +/gm, '')
-          )
-        }
-
         exportNodes.push(childNode)
         continue
       }

packages/mdx/package.json

@@ -36,6 +36,7 @@
     "detab": "^2.0.0",
     "hast-util-raw": "^5.0.0",
     "mdast-util-to-hast": "^4.0.0",
+    "remark-mdx": "^0.18.2",
     "remark-parse": "^6.0.0",
     "remark-squeeze-paragraphs": "^3.0.1",
     "to-style": "^1.3.3",

packages/mdx/test/index.test.js

@@ -279,35 +279,6 @@ it('Should support semicolons in default export statement', async () => {
   expect(() => parse(result)).not.toThrow()
 })
 
-it('Should throw when exporting default via named export', async () => {
-  await expect(mdx(`export { default } from './Layout'`)).rejects.toThrow()
-  await expect(mdx(`export { Layout as default }`)).rejects.toThrow()
-  await expect(
-    mdx(`export { foo as bar, Layout as default }`)
-  ).rejects.toThrow()
-
-  // Ensure that word "default" appearing in export node does not throw
-  const fixture1 = `export const meta = {
-  description: 'better default as behavior.'
-}`
-  await expect(mdx(fixture1)).resolves.toContain(fixture1)
-
-  // Ensure that a full export pattern within metadata does not throw
-  const fixture2 = `export const meta = {
-decription: 'How to use es6 exports',
-examples: [
-  'export { default } from "./example"',
-  'export { foo as default }'
-]
-}`
-  await expect(mdx(fixture2)).resolves.toContain(fixture2)
-
-  // Ensure that `export { default as x }` pattern does not throw
-  await expect(
-    mdx(`export { default as MyComp } from './MyComp'`)
-  ).resolves.toContain(`export { default as MyComp } from './MyComp'`)
-})
-
 it('Should not include export wrapper if skipExport is true', async () => {
   const result = await mdx('> test\n\n> `test`', {skipExport: true})
 
@@ -398,6 +369,7 @@ test('Should handle layout props', () => {
   expect(result).toMatchInlineSnapshot(`
 "/* @jsx mdx */
 import { Baz } from './Fixture'
+
 import { Buz } from './Fixture'
 export const foo = {
   hi: \`Fudge \${Baz.displayName || 'Baz'}\`,

yarn.lock

@@ -10482,6 +10482,11 @@ parse5@^5.0.0:
   resolved "https://registry.yarnpkg.com/parse5/-/parse5-5.1.0.tgz#c59341c9723f414c452975564c7c00a68d58acd2"
   integrity sha512-fxNG2sQjHvlVAYmzBZS9YlDp6PTSSDwa98vkD4QgVDDCAo84z5X1t5XyJQ62ImdLXx5NdIIfihey6xpum9/gRQ==
 
+parse5@^2.1.5:
+  version "2.2.3"
+  resolved "https://registry.yarnpkg.com/parse5/-/parse5-2.2.3.tgz#0c4fc41c1000c5e6b93d48b03f8083837834e9f6"
+  integrity sha1-DE/EHBAAxea5PUiwP4CDg3g06fY=
+
 parseurl@^1.3.2, parseurl@~1.3.2:
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/parseurl/-/parseurl-1.3.2.tgz#fc289d4ed8993119460c156253262cdc8de65bf3"