fix(react-email): Null byte characters being rendered in the preview (#1773)

Author: gabrielmfern

.changeset/clever-meals-vanish.md

@@ -0,0 +1,5 @@
+---
+"react-email": patch
+---
+
+fix null byte characters being rendered in the preview server

packages/react-email/src/actions/render-email-by-path.tsx

@@ -83,7 +83,10 @@ export const renderEmailByPath = async (
     });
 
     return {
-      markup,
+      // This ensures that no null byte character ends up in the rendered
+      // markup making users suspect of any issues. These null byte characters
+      // only seem to happen with React 18, as it has no similar incident with React 19.
+      markup: markup.replaceAll('\0', ''),
       plainText,
       reactMarkup,
     };

packages/render/src/node/read-stream.ts

@@ -29,10 +29,10 @@ export const readStream = async (
     });
     stream.pipe(writable);
 
-    return new Promise<string>((resolve, reject) => {
+    await new Promise<void>((resolve, reject) => {
       writable.on("error", reject);
       writable.on("close", () => {
-        resolve(result);
+        resolve();
       });
     });
   }