fix(clerk-js): Throw error when opening <Checkout /> without a session

.changeset/puny-pants-cough.md

@@ -0,0 +1,5 @@
+---
+'@clerk/clerk-js': patch
+---
+
+Throw error in development when opening `<Checkout />` without a session. 

packages/clerk-js/src/core/clerk.ts

@@ -554,6 +554,15 @@ export class Clerk implements ClerkInterface {
       }
       return;
     }
+    if (noUserExists(this)) {
+      if (this.#instanceType === 'development') {
+        throw new ClerkRuntimeError(warnings.cannotOpenCheckout, {
+          code: CANNOT_RENDER_USER_MISSING_ERROR_CODE,
+        });
+      }
+      return;
+    }
+
     void this.#componentControls
       .ensureMounted({ preloadHint: 'Checkout' })
       .then(controls => controls.openDrawer('checkout', props || {}));

packages/clerk-js/src/core/warnings.ts

@@ -34,6 +34,8 @@ const warnings = {
   cannotRenderAnyCommerceComponent: createMessageForDisabledCommerce,
   cannotOpenUserProfile:
     'The UserProfile modal cannot render unless a user is signed in. Since no user is signed in, this is no-op.',
+  cannotOpenCheckout:
+    'The Checkout drawer cannot render unless a user is signed in. Since no user is signed in, this is no-op.',
   cannotOpenSignInOrSignUp:
     'The SignIn or SignUp modals do not render when a user is already signed in, unless the application allows multiple sessions. Since a user is signed in and this application only allows a single session, this is no-op.',
 };