fix(plugin-react): check for import React statement in .js files (#6320)

* fix: reactPlugin skip inject react hmr code to workerFile (fix #6148)

* Revert "fix: reactPlugin skip inject react hmr code to workerFile (fix #6148)"

This reverts commit 136883d.

* fix(plugin-react): check for import React statement in .js files

…instead of using naïve `code.includes("react")` check

Co-authored-by: Alec Larson <1925840+aleclarson@users.noreply.github.com>

packages/plugin-react/src/index.ts

@@ -118,7 +118,7 @@ export default function viteReact(opts: Options = {}): PluginOption[] {
         let useFastRefresh = false
         if (!skipFastRefresh && !ssr && !isNodeModules) {
           // Modules with .js or .ts extension must import React.
-          const isReactModule = isJSX || code.includes('react')
+          const isReactModule = isJSX || importReactRE.test(code)
           if (isReactModule && filter(id)) {
             useFastRefresh = true
             plugins.push([