feat(sveltekit): Introduce client-side handleError wrapper

packages/sveltekit/package.json

@@ -13,6 +13,18 @@
   "module": "build/esm/index.server.js",
   "browser": "build/esm/index.client.js",
   "types": "build/types/index.types.d.ts",
+  "exports": {
+    "browser": {
+      "import": "./build/esm/index.client.js",
+      "require": "./build/cjs/index.client.js",
+      "default": "./build/esm/index.client.js"
+    },
+    "node": {
+      "import": "./build/esm/index.server.js",
+      "require": "./build/cjs/index.server.js",
+      "default": "./build/esm/index.server.js"
+    }
+  },
   "publishConfig": {
     "access": "public"
   },
@@ -28,7 +40,7 @@
     "magic-string": "^0.30.0"
   },
   "devDependencies": {
-    "@sveltejs/kit": "^1.5.0",
+    "@sveltejs/kit": "^1.11.0",
     "vite": "4.0.0",
     "typescript": "^4.9.3"
   },

packages/sveltekit/src/client/handleError.ts

@@ -0,0 +1,28 @@
+import { captureException } from '@sentry/svelte';
+import { addExceptionMechanism } from '@sentry/utils';
+// For now disable the import/no-unresolved rule, because we don't have a way to
+// tell eslint that we are only importing types from the @sveltejs/kit package without
+// adding a custom resolver, which will take too much time.
+// eslint-disable-next-line import/no-unresolved
+import type { HandleClientError, NavigationEvent } from '@sveltejs/kit';
+
+/**
+ * Wrapper for the SvelteKit error handler that sends the error to Sentry.
+ *
+ * @param handleError The original SvelteKit error handler.
+ */
+export function wrapHandleError(handleError: HandleClientError): HandleClientError {
+  return (input: { error: unknown; event: NavigationEvent }): ReturnType<HandleClientError> => {
+    captureException(input.error, scope => {
+      scope.addEventProcessor(event => {
+        addExceptionMechanism(event, {
+          type: 'sveltekit',
+          handled: false,
+        });
+        return event;
+      });
+      return scope;
+    });
+    return handleError(input);
+  };
+}

packages/sveltekit/src/client/index.ts

@@ -1,3 +1,7 @@
 export * from '@sentry/svelte';
 
 export { init } from './sdk';
+export { wrapHandleError } from './handleError';
+
+// Just here so that eslint is happy until we export more stuff here
+export const PLACEHOLDER_CLIENT = 'PLACEHOLDER';

packages/sveltekit/test/client/handleError.test.ts

@@ -0,0 +1,83 @@
+import { Scope } from '@sentry/svelte';
+
+// For now disable the import/no-unresolved rule, because we don't have a way to
+// tell eslint that we are only importing types from the @sveltejs/kit package without
+// adding a custom resolver, which will take too much time.
+// eslint-disable-next-line import/no-unresolved
+import type { HandleClientError, NavigationEvent } from '@sveltejs/kit';
+
+import { wrapHandleError } from '../../src/client/handleError';
+
+const mockCaptureException = jest.fn();
+let mockScope = new Scope();
+
+jest.mock('@sentry/svelte', () => {
+  const original = jest.requireActual('@sentry/core');
+  return {
+    ...original,
+    captureException: (err: unknown, cb: (arg0: unknown) => unknown) => {
+      cb(mockScope);
+      mockCaptureException(err, cb);
+      return original.captureException(err, cb);
+    },
+  };
+});
+
+const mockAddExceptionMechanism = jest.fn();
+
+jest.mock('@sentry/utils', () => {
+  const original = jest.requireActual('@sentry/utils');
+  return {
+    ...original,
+    addExceptionMechanism: (...args: unknown[]) => mockAddExceptionMechanism(...args),
+  };
+});
+
+function handleError(_input: { error: unknown; event: NavigationEvent }): ReturnType<HandleClientError> {
+  return {
+    message: 'Whoops!',
+  };
+}
+
+const navigationEvent: NavigationEvent = {
+  params: {
+    id: '123',
+  },
+  route: {
+    id: 'users/[id]',
+  },
+  url: new URL('http://example.org/users/123'),
+};
+
+describe('handleError', () => {
+  beforeEach(() => {
+    mockCaptureException.mockClear();
+    mockAddExceptionMechanism.mockClear();
+    mockScope = new Scope();
+  });
+
+  it('calls captureException', async () => {
+    const wrappedHandleError = wrapHandleError(handleError);
+    const mockError = new Error('test');
+    const returnVal = await wrappedHandleError({ error: mockError, event: navigationEvent });
+
+    expect(returnVal!.message).toEqual('Whoops!');
+    expect(mockCaptureException).toHaveBeenCalledTimes(1);
+    expect(mockCaptureException).toHaveBeenCalledWith(mockError, expect.any(Function));
+  });
+
+  it('adds an exception mechanism', async () => {
+    const addEventProcessorSpy = jest.spyOn(mockScope, 'addEventProcessor').mockImplementationOnce(callback => {
+      void callback({}, { event_id: 'fake-event-id' });
+      return mockScope;
+    });
+
+    const wrappedHandleError = wrapHandleError(handleError);
+    const mockError = new Error('test');
+    await wrappedHandleError({ error: mockError, event: navigationEvent });
+
+    expect(addEventProcessorSpy).toBeCalledTimes(1);
+    expect(mockAddExceptionMechanism).toBeCalledTimes(1);
+    expect(mockAddExceptionMechanism).toBeCalledWith({}, { handled: false, type: 'sveltekit' });
+  });
+});

yarn.lock

@@ -4205,7 +4205,7 @@
   dependencies:
     highlight.js "^9.15.6"
 
-"@sveltejs/kit@^1.5.0":
+"@sveltejs/kit@^1.11.0":
   version "1.11.0"
   resolved "https://registry.yarnpkg.com/@sveltejs/kit/-/kit-1.11.0.tgz#23f233c351e5956356ba6f3206e40637c5f5dbda"
   integrity sha512-PwViZcMoLgEU/jhLoSyjf5hSrHS67wvSm0ifBo4prP9irpGa5HuPOZeVDTL5tPDSBoKxtdYi1zlGdoiJfO86jA==