fix: use null check for keyName fallback and tailor error messages

Use keyName == null instead of truthiness check so empty strings
don't incorrectly trigger fallback. Error messages now only suggest
SUPABASE_*_KEY for the default key, not for named keys.

Author: tomaspozo

src/core/create-admin-client.ts

@@ -13,12 +13,14 @@ export function createAdminClient(
 
   const name = keyName ?? 'default'
   const keys = resolved.secretKeys
-  const secretKey = keys[name] ?? (keyName ? undefined : Object.values(keys)[0])
+  const secretKey =
+    keys[name] ?? (keyName == null ? Object.values(keys)[0] : undefined)
   if (!secretKey) {
-    throw new EnvError(
-      `No "${name}" secret key found. Set SUPABASE_SECRET_KEY or include a "${name}" entry in SUPABASE_SECRET_KEYS.`,
-      'MISSING_SECRET_KEY',
-    )
+    const msg =
+      name === 'default'
+        ? 'No default secret key found. Set SUPABASE_SECRET_KEY or include a "default" entry in SUPABASE_SECRET_KEYS.'
+        : `No "${name}" secret key found. Include a "${name}" entry in SUPABASE_SECRET_KEYS.`
+    throw new EnvError(msg, 'MISSING_SECRET_KEY')
   }
 
   return createClient(resolved.url, secretKey, {

src/core/create-context-client.ts

@@ -14,12 +14,14 @@ export function createContextClient(
 
   const name = keyName ?? 'default'
   const keys = resolved.publishableKeys
-  const anonKey = keys[name] ?? (keyName ? undefined : Object.values(keys)[0])
+  const anonKey =
+    keys[name] ?? (keyName == null ? Object.values(keys)[0] : undefined)
   if (!anonKey) {
-    throw new EnvError(
-      `No "${name}" publishable key found. Set SUPABASE_PUBLISHABLE_KEY or include a "${name}" entry in SUPABASE_PUBLISHABLE_KEYS.`,
-      'MISSING_PUBLISHABLE_KEY',
-    )
+    const msg =
+      name === 'default'
+        ? 'No default publishable key found. Set SUPABASE_PUBLISHABLE_KEY or include a "default" entry in SUPABASE_PUBLISHABLE_KEYS.'
+        : `No "${name}" publishable key found. Include a "${name}" entry in SUPABASE_PUBLISHABLE_KEYS.`
+    throw new EnvError(msg, 'MISSING_PUBLISHABLE_KEY')
   }
 
   return createClient(resolved.url, anonKey, {