fix(create-email): validate npm registry response and exit on invalid version (#3741)

Signed-off-by: Tyagiquamar <mohdquamartyagi@gmail.com>
Co-authored-by: Felipe Freitag <felipe.freitag@resend.com>

Author: Tyagiquamar

.changeset/create-email-validate-npm-response.md

@@ -0,0 +1,5 @@
+---
+"create-email": patch
+---
+
+Exit with an error when the npm registry request fails or returns an invalid version, instead of writing `undefined` into the starter's package.json.

packages/create-email/src/index.js

@@ -19,17 +19,24 @@ const getLatestVersionOfTag = async (packageName, tag) => {
   const response = await fetch(
     `https://registry.npmjs.org/${packageName}/${tag}`,
   );
-  const data = await response.json();
 
-  if (typeof data === 'string' && data.startsWith('version not found')) {
+  if (response.status === 404) {
     console.error(`Tag ${tag} does not exist for ${packageName}.`);
     process.exit(1);
   }
 
-  const { version } = data;
+  if (!response.ok) {
+    console.error(
+      `Failed to fetch tag ${tag} for ${packageName}: HTTP ${response.status}`,
+    );
+    process.exit(1);
+  }
 
-  if (!/^\d+\.\d+\.\d+.*$/.test(version)) {
+  const { version } = await response.json();
+
+  if (!version || !/^\d+\.\d+\.\d+.*$/.test(version)) {
     console.error('Invalid version received, something has gone very wrong.');
+    process.exit(1);
   }
 
   return version;