Use an alias for react-dom/client if not installed (#410)

This implements a suggestion in vitejs/vite#6007 (comment)
to alias react-dom/client to our placeholder file when the dependency is not found.

In vite 3.0, our current approach will no longer work, and we'll need to use this method instead.

packages/builder-vite/code-generator-plugin.ts

@@ -15,7 +15,6 @@ import { virtualAddonSetupFile, virtualFileId, virtualPreviewFile, virtualStorie
 export function codeGeneratorPlugin(options: ExtendedOptions): Plugin {
   const iframePath = path.resolve(__dirname, '..', 'input', 'iframe.html');
   let iframeId: string;
-  let projRoot: string;
 
   // noinspection JSUnusedGlobalSymbols
   return {
@@ -59,9 +58,23 @@ export function codeGeneratorPlugin(options: ExtendedOptions): Plugin {
           input: iframePath,
         };
       }
+
+      // Detect if react 18 is installed.  If not, alias it to a virtual placeholder file.
+      try {
+        require.resolve('react-dom/client', { paths: [config.root || process.cwd()] });
+      } catch (e) {
+        if (isNodeError(e) && e.code === 'MODULE_NOT_FOUND') {
+          config.resolve = {
+            ...config.resolve,
+            alias: {
+              ...config.resolve?.alias,
+              'react-dom/client': path.resolve(__dirname, '..', 'input', 'react-dom-client-placeholder.js'),
+            },
+          };
+        }
+      }
     },
     configResolved(config) {
-      projRoot = config.root;
       iframeId = `${config.root}/iframe.html`;
     },
     resolveId(source) {
@@ -75,14 +88,6 @@ export function codeGeneratorPlugin(options: ExtendedOptions): Plugin {
         return virtualPreviewFile;
       } else if (source === virtualAddonSetupFile) {
         return virtualAddonSetupFile;
-        // Avoid error in react < 18 projects
-      } else if (source === 'react-dom/client') {
-        try {
-          return require.resolve('react-dom/client', { paths: [projRoot] });
-        } catch (e) {
-          // This is not a react 18 project, need to stub out to avoid error
-          return path.resolve(__dirname, '..', 'input', 'react-dom-client-placeholder.js');
-        }
       }
     },
     async load(id) {
@@ -123,3 +128,6 @@ export function codeGeneratorPlugin(options: ExtendedOptions): Plugin {
     },
   };
 }
+
+// Refines an error received from 'catch' to be a NodeJS exception
+const isNodeError = (error: unknown): error is NodeJS.ErrnoException => error instanceof Error;

packages/builder-vite/optimizeDeps.ts

@@ -109,17 +109,6 @@ export async function getOptimizeDeps(
   const stories = absoluteStories.map((storyPath) => normalizePath(path.relative(root, storyPath)));
   const resolvedConfig = await resolveConfig(config, 'serve', 'development');
 
-  const exclude = [];
-  // This is necessary to support react < 18 with new versions of @storybook/react that support react 18.
-  // TODO: narrow this down to just framework === 'react'.  But causes a vue dev start problem in this monorepo.
-  try {
-    require.resolve('react-dom/client', { paths: [config.root] });
-  } catch (e) {
-    if (isNodeError(e) && e.code === 'MODULE_NOT_FOUND') {
-      exclude.push('react-dom/client');
-    }
-  }
-
   // This function converts ids which might include ` > ` to a real path, if it exists on disk.
   // See https://github.com/vitejs/vite/blob/67d164392e8e9081dc3f0338c4b4b8eea6c5f7da/packages/vite/src/node/optimizer/index.ts#L182-L199
   const resolve = resolvedConfig.createResolver({ asSrc: false });
@@ -131,10 +120,5 @@ export async function getOptimizeDeps(
     // We need Vite to precompile these dependencies, because they contain non-ESM code that would break
     // if we served it directly to the browser.
     include,
-    // In some cases we need to prevent deps from being pre-bundled
-    exclude,
   };
 }
-
-// Refines an error received from 'catch' to be a NodeJS exception
-const isNodeError = (error: unknown): error is NodeJS.ErrnoException => error instanceof Error;