fix(react-email): resolve aliased dynamic import directories on Windows

.changeset/windows-aliased-dynamic-import-reload.md

@@ -0,0 +1,5 @@
+---
+'react-email': patch
+---
+
+Resolve tsconfig path aliases in dynamic import template literals on Windows, so editing a file inside an aliased directory reloads the preview.

packages/react-email/src/cli/utils/preview/hot-reloading/resolve-path-aliases.spec.ts

@@ -1,5 +1,8 @@
 import path from 'node:path';
-import { resolvePathAliases } from './resolve-path-aliases.js';
+import {
+  resolveAliasedDirectoryPrefix,
+  resolvePathAliases,
+} from './resolve-path-aliases.js';
 
 test('resolveImports()', async () => {
   expect(
@@ -9,3 +12,21 @@ test('resolveImports()', async () => {
     ),
   ).toEqual(['./some-file']);
 });
+
+test('resolveAliasedDirectoryPrefix() accepts platform-normalized separators', () => {
+  const sourceDirectory = path.resolve(
+    import.meta.dirname,
+    './test/aliased-import-graph/src',
+  );
+  const localesDirectory = path.join(sourceDirectory, 'locales');
+
+  expect(resolveAliasedDirectoryPrefix('@/locales', sourceDirectory)).toEqual(
+    localesDirectory,
+  );
+
+  // On Windows, `path.normalize()` turns the specifier's forward slashes into
+  // backslashes before the prefix reaches this function.
+  expect(resolveAliasedDirectoryPrefix('@\\locales', sourceDirectory)).toEqual(
+    localesDirectory,
+  );
+});

packages/react-email/src/cli/utils/preview/hot-reloading/resolve-path-aliases.ts

@@ -51,7 +51,13 @@ export const resolveAliasedDirectoryPrefix = (
     configLoadResult.absoluteBaseUrl,
     configLoadResult.paths,
   );
-  const resolved = matchPath(prefix, undefined, isExistingDirectory, [
+
+  // `paths` patterns are always written with forward slashes, but the prefix may
+  // have been normalized with the platform separator (backslashes on Windows) by
+  // `path.normalize()`. Restore import specifier separators so patterns match.
+  const importPrefix = prefix.replace(/\\/g, '/');
+
+  const resolved = matchPath(importPrefix, undefined, isExistingDirectory, [
     '.tsx',
     '.ts',
     '.js',