node-loader: remove fixRuntimeWithoutExportMap

Previously, we by default fixed automatic JSX runtimes
without a valid export map.
That is because React 16 and 17 were broken.
All other JSX runtimes, such as Vue or Preact, were valid.
As of React 18, they now use a valid export map.
Meaning this workaround is no longer needed.

packages/node-loader/index.js

@@ -1,5 +1,5 @@
 /**
- * @typedef {import('./lib/index.js').CompileOptions} Options
+ * @typedef {import('./lib/index.js').Options} Options
  */
 
 import {createLoader} from './lib/index.js'

packages/node-loader/lib/index.js

@@ -1,18 +1,5 @@
 /**
- * @typedef {import('@mdx-js/mdx/lib/compile.js').CompileOptions} CompileOptions
- */
-
-/**
- * @typedef LoaderOptions
- *   Extra configuration.
- * @property {boolean | null | undefined} [fixRuntimeWithoutExportMap=true]
- *   Several JSX runtimes, notably React below 18 and Emotion below 11.10.0,
- *   don’t yet have a proper export map set up (default: `true`).
- *   Export maps are needed to map `xxx/jsx-runtime` to an actual file in ESM.
- *   This option fixes React et al by turning those into `xxx/jsx-runtime.js`.
- *
- * @typedef {CompileOptions & LoaderOptions} Options
- *   Configuration.
+ * @typedef {import('@mdx-js/mdx/lib/compile.js').CompileOptions} Options
  */
 
 import fs from 'node:fs/promises'
@@ -32,14 +19,6 @@ export function createLoader(options) {
   const options_ = options || {}
   const {extnames, process} = createFormatAwareProcessors(options_)
   const regex = extnamesToRegex(extnames)
-  let fixRuntimeWithoutExportMap = options_.fixRuntimeWithoutExportMap
-
-  if (
-    fixRuntimeWithoutExportMap === null ||
-    fixRuntimeWithoutExportMap === undefined
-  ) {
-    fixRuntimeWithoutExportMap = true
-  }
 
   return {load, getFormat, transformSource}
 
@@ -60,14 +39,8 @@ export function createLoader(options) {
     if (url.protocol === 'file:' && regex.test(url.pathname)) {
       const value = await fs.readFile(url)
       const file = await process(new VFile({value, path: url}))
-      let source = String(file)
-
-      /* c8 ignore next 3 -- to do: remove. */
-      if (fixRuntimeWithoutExportMap) {
-        source = String(file).replace(/\/jsx-runtime(?=["'])/, '$&.js')
-      }
 
-      return {format: 'module', shortCircuit: true, source}
+      return {format: 'module', shortCircuit: true, source: String(file)}
     }
 
     return defaultLoad(href, context, defaultLoad)
@@ -113,13 +86,7 @@ export function createLoader(options) {
 
     if (url.protocol === 'file:' && regex.test(url.pathname)) {
       const file = await process(new VFile({path: new URL(context.url), value}))
-      let source = String(file)
-
-      if (fixRuntimeWithoutExportMap) {
-        source = String(file).replace(/\/jsx-runtime(?=["'])/, '$&.js')
-      }
-
-      return {source}
+      return {source: String(file)}
     }
 
     return defaultTransformSource(value, context, defaultTransformSource)

packages/node-loader/package.json

@@ -43,7 +43,7 @@
   "devDependencies": {},
   "scripts": {
     "test": "npm run test-coverage",
-    "test-api": "node --conditions development --loader=./test/react-18-node-loader.js test/index.js",
+    "test-api": "node --conditions development --loader=@mdx-js/node-loader test/index.js",
     "test-coverage": "c8 --100 --reporter lcov npm run test-api"
   },
   "xo": {

packages/node-loader/readme.md

@@ -112,20 +112,6 @@ Create a Node ESM loader to compile MDX to JS.
 `options` are the same as [`compile` from `@mdx-js/mdx`][options].
 One extra field is supported:
 
-###### `options.fixRuntimeWithoutExportMap`
-
-Fix broken export maps (`boolean`, default: `true`).
-
-Several JSX runtimes, notably React below 18 and Emotion below 11.10.0, don’t
-have a proper export map set up.
-Export maps are needed to map `xxx/jsx-runtime` to an actual file in ESM.
-This option fixes React et al by turning those into `xxx/jsx-runtime.js`.
-
-> 👉 **Note**: If you are using recent React, or other proper packages, you
-> have to turn this field off.
-> See the example below on how to configure your loader.
-> Pass `fixRuntimeWithoutExportMap: false` in options to it.
-
 ###### Example
 
 `my-loader.js`:

packages/node-loader/test/index.js

@@ -38,7 +38,7 @@ test('@mdx-js/node-loader', async function (t) {
         await fs.rm(mdxUrl)
 
         throw new Error(
-          'Please run Node with `--loader=./test/react-18-node-loader.js` to test the ESM loader'
+          'Please run Node with `--loader=@mdx-js/node-loader` to test the ESM loader'
         )
       }
 

website/mdx-config.js

@@ -48,8 +48,6 @@ import {config} from '../docs/_config.js'
 
 /** @type {Readonly<CompileOptions>} */
 const options = {
-  // To do: remove.
-  fixRuntimeWithoutExportMap: false,
   recmaPlugins: [recmaInjectMeta],
   rehypePlugins: [
     rehypePrettyCodeBlocks,