vite: Don't watch files or invalidate VE modules during SSR (#1617)

Author: askoufis

.changeset/weak-boats-walk.md

@@ -0,0 +1,7 @@
+---
+'@vanilla-extract/vite-plugin': patch
+---
+
+Don't watch files or invalidate VE modules during SSR
+
+Fixes a bug where a dependent of a Vanilla Extract module could be evaulated multiple times during `ssrLoadModule`, potentially causing bugs with singleton variables such as React context.

packages/vite-plugin/src/index.ts

@@ -183,7 +183,7 @@ export function vanillaExtractPlugin({
     closeWatcher() {
       return compiler?.close();
     },
-    async transform(code, id) {
+    async transform(code, id, options = {}) {
       const [validId] = id.split('?');
 
       if (!cssFileFilter.test(validId)) {
@@ -214,8 +214,8 @@ export function vanillaExtractPlugin({
           map: { mappings: '' },
         };
 
-        // We don't need to watch files in build mode
-        if (isBuild) {
+        // We don't need to watch files or invalidate modules in build mode or during SSR
+        if (isBuild || options.ssr) {
           return result;
         }