fix(plugin-react): apply babel.plugins to project files only (vitejs#5255)

Author: aleclarson

packages/plugin-react/src/index.ts

@@ -160,15 +160,17 @@ export default function viteReact(opts: Options = {}): PluginOption[] {
     },
     async transform(code, id, ssr) {
       if (/\.(mjs|[tj]sx?)$/.test(id)) {
+        const isJSX = id.endsWith('x')
         const isNodeModules = id.includes('/node_modules/')
-        const isProjectFile = id.startsWith(projectRoot + '/') && !isNodeModules
+        const isProjectFile =
+          !isNodeModules && (id[0] === '\0' || id.startsWith(projectRoot + '/'))
 
         const plugins = isProjectFile ? [...babelOptions.plugins] : []
 
         let useFastRefresh = false
         if (!skipFastRefresh && !ssr && !isNodeModules) {
           // Modules with .js or .ts extension must import React.
-          const isReactModule = id.endsWith('x') || importReactRE.test(code)
+          const isReactModule = isJSX || importReactRE.test(code)
           if (isReactModule && filter(id)) {
             useFastRefresh = true
             plugins.push([
@@ -179,7 +181,7 @@ export default function viteReact(opts: Options = {}): PluginOption[] {
         }
 
         let ast: t.File | null | undefined
-        if (!isProjectFile || id.endsWith('x')) {
+        if (!isProjectFile || isJSX) {
           if (useAutomaticRuntime) {
             // By reverse-compiling "React.createElement" calls into JSX,
             // React elements provided by dependencies will also use the

packages/plugin-react/src/jsx-runtime/restore-jsx.ts

@@ -4,15 +4,23 @@ type RestoredJSX = [result: t.File | null | undefined, isCommonJS: boolean]
 
 let babelRestoreJSX: Promise<PluginItem> | undefined
 
+const jsxNotFound: RestoredJSX = [null, false]
+
 /** Restore JSX from `React.createElement` calls */
 export async function restoreJSX(
   babel: typeof import('@babel/core'),
   code: string,
   filename: string
 ): Promise<RestoredJSX> {
+  // Avoid parsing the optimized react-dom since it will never
+  // contain compiled JSX and it's a pretty big file (800kb).
+  if (filename.includes('/.vite/react-dom.js')) {
+    return jsxNotFound
+  }
+
   const [reactAlias, isCommonJS] = parseReactAlias(code)
   if (!reactAlias) {
-    return [null, false]
+    return jsxNotFound
   }
 
   const reactJsxRE = new RegExp(
@@ -28,7 +36,7 @@ export async function restoreJSX(
   })
 
   if (!hasCompiledJsx) {
-    return [null, false]
+    return jsxNotFound
   }
 
   // Support modules that use `import {Fragment} from 'react'`