fix(plugin-react): wrong substitution causes React is not defined

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

@@ -4,6 +4,10 @@
  */
 import type * as babel from '@babel/core'
 
+interface PluginOptions {
+  reactAlias: string
+}
+
 /**
  * Visitor factory for babel, converting React.createElement(...) to <jsx ...>...</jsx>
  *
@@ -17,7 +21,10 @@ import type * as babel from '@babel/core'
  *
  * Any of those arguments might also be missing (undefined) and/or invalid.
  */
-export default function ({ types: t }: typeof babel): babel.PluginObj {
+export default function (
+  { types: t }: typeof babel,
+  { reactAlias = 'React' }: PluginOptions
+): babel.PluginObj {
   /**
    * Get a `JSXElement` from a `CallExpression`.
    * Returns `null` if this impossible.
@@ -48,7 +55,7 @@ export default function ({ types: t }: typeof babel): babel.PluginObj {
     if (
       t.isJSXMemberExpression(name) &&
       t.isJSXIdentifier(name.object) &&
-      name.object.name === 'React' &&
+      name.object.name === reactAlias &&
       name.property.name === 'Fragment'
     ) {
       return t.jsxFragment(
@@ -182,7 +189,7 @@ export default function ({ types: t }: typeof babel): babel.PluginObj {
   const isReactCreateElement = (node: any) =>
     t.isCallExpression(node) &&
     t.isMemberExpression(node.callee) &&
-    t.isIdentifier(node.callee.object, { name: 'React' }) &&
+    t.isIdentifier(node.callee.object, { name: reactAlias }) &&
     t.isIdentifier(node.callee.property, { name: 'createElement' }) &&
     !node.callee.computed
 

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

@@ -81,7 +81,10 @@ describe('restore-jsx', () => {
     expect(
       await jsx(`import React__default, { PureComponent, Component, forwardRef, memo, createElement } from 'react';
       React__default.createElement(foo)`)
-    ).toBeNull()
+    ).toMatchInlineSnapshot(`
+      "import React__default, { PureComponent, Component, forwardRef, memo, createElement } from 'react';
+      React__default.createElement(foo);"
+    `)
     expect(
       await jsx(`import React__default, { PureComponent, Component, forwardRef, memo, createElement } from 'react';
       React__default.createElement("h1")`)
@@ -104,7 +107,12 @@ describe('restore-jsx', () => {
     expect(
       await jsx(`import React__default, { PureComponent, Component, forwardRef, memo, createElement } from 'react';
       React__default.createElement(foo, {hi: there})`)
-    ).toBeNull()
+    ).toMatchInlineSnapshot(`
+      "import React__default, { PureComponent, Component, forwardRef, memo, createElement } from 'react';
+      React__default.createElement(foo, {
+        hi: there
+      });"
+    `)
     expect(
       await jsx(`import React__default, { PureComponent, Component, forwardRef, memo, createElement } from 'react';
     React__default.createElement("h1", {hi: there})`)
@@ -114,4 +122,26 @@ describe('restore-jsx', () => {
       React__default.createElement(Foo, {hi: there})`)
     ).toMatch(`<Foo hi={there} />;`)
   })
+
+  it('should handle Fragment', async () => {
+    expect(
+      await jsx(`import R, { Fragment } from 'react';
+        R.createElement(Fragment)
+      `)
+    ).toMatchInlineSnapshot(`
+      "import R, { Fragment } from 'react';
+      <Fragment />;"
+    `)
+  })
+
+  it('should handle Fragment alias', async () => {
+    expect(
+      await jsx(`import RA, { Fragment as F } from 'react';
+        RA.createElement(F, null, RA.createElement(RA.Fragment))
+      `)
+    ).toMatchInlineSnapshot(`
+      "import RA, { Fragment as F } from 'react';
+      <F><></></F>;"
+    `)
+  })
 })

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

@@ -33,34 +33,12 @@ export async function restoreJSX(
     return jsxNotFound
   }
 
-  let hasCompiledJsx = false
-
-  const fragmentPattern = `\\b${reactAlias}\\.Fragment\\b`
-  const createElementPattern = `\\b${reactAlias}\\.createElement\\(\\s*([A-Z"'][\\w$.]*["']?)`
-
-  // Replace the alias with "React" so JSX can be reverse compiled.
-  code = code
-    .replace(new RegExp(fragmentPattern, 'g'), () => {
-      hasCompiledJsx = true
-      return 'React.Fragment'
-    })
-    .replace(new RegExp(createElementPattern, 'g'), (original, component) => {
-      if (/^[a-z][\w$]*$/.test(component)) {
-        // Take care not to replace the alias for `createElement` calls whose
-        // component is a lowercased variable, since the `restoreJSX` Babel
-        // plugin leaves them untouched.
-        return original
-      }
-      hasCompiledJsx = true
-      return (
-        'React.createElement(' +
-        // Assume `Fragment` is equivalent to `React.Fragment` so modules
-        // that use `import {Fragment} from 'react'` are reverse compiled.
-        (component === 'Fragment' ? 'React.Fragment' : component)
-      )
-    })
+  const reactJsxRE = new RegExp(
+    `\\b${reactAlias}\\.(createElement|Fragment)\\b`,
+    'g'
+  )
 
-  if (!hasCompiledJsx) {
+  if (!reactJsxRE.test(code)) {
     return jsxNotFound
   }
 
@@ -73,7 +51,7 @@ export async function restoreJSX(
     parserOpts: {
       plugins: ['jsx']
     },
-    plugins: [await getBabelRestoreJSX()]
+    plugins: [[await getBabelRestoreJSX(), { reactAlias }]]
   })
 
   return [result?.ast, isCommonJS]