Refactoring and additional tests.

Author: kinyoklion

packages/telemetry/browser-telemetry/__tests__/BrowserTelemetryImpl.test.ts

@@ -1,3 +1,4 @@
+import { LDClientLogging } from '../src/api';
 import { LDClientTracking } from '../src/api/client/LDClientTracking';
 import BrowserTelemetryImpl from '../src/BrowserTelemetryImpl';
 import { ParsedOptions } from '../src/options';
@@ -482,3 +483,42 @@ it('only logs breadcrumb filter error once', () => {
     'LaunchDarkly - Browser Telemetry: Error applying breadcrumb filters: Error: Filter error',
   );
 });
+
+it('uses the client logger when no logger is provided', () => {
+  const options: ParsedOptions = {
+    ...defaultOptions,
+    breadcrumbs: {
+      ...defaultOptions.breadcrumbs,
+      filters: [
+        () => {
+          throw new Error('Filter error');
+        },
+      ],
+    },
+  };
+
+  const telemetry = new BrowserTelemetryImpl(options);
+
+  const mockClientWithLogging: jest.Mocked<LDClientLogging & LDClientTracking> = {
+    logger: {
+      warn: jest.fn(),
+    },
+    track: jest.fn(),
+  };
+
+  telemetry.register(mockClientWithLogging);
+
+  // Add multiple breadcrumbs that will trigger the filter error
+  telemetry.addBreadcrumb({
+    type: 'custom',
+    data: { id: 1 },
+    timestamp: Date.now(),
+    class: 'custom',
+    level: 'info',
+  });
+
+  expect(mockClientWithLogging.logger.warn).toHaveBeenCalledTimes(1);
+  expect(mockClientWithLogging.logger.warn).toHaveBeenCalledWith(
+    'LaunchDarkly - Browser Telemetry: Error applying breadcrumb filters: Error: Filter error',
+  );
+});

packages/telemetry/browser-telemetry/src/BrowserTelemetryImpl.ts

@@ -5,7 +5,7 @@
  */
 import type { LDContext, LDEvaluationDetail, LDInspection } from '@launchdarkly/js-client-sdk';
 
-import { BreadcrumbFilter, LDClientTracking, MinLogger } from './api';
+import { BreadcrumbFilter, LDClientLogging, LDClientTracking, MinLogger } from './api';
 import { Breadcrumb, FeatureManagementBreadcrumb } from './api/Breadcrumb';
 import { BrowserTelemetry } from './api/BrowserTelemetry';
 import { Collector } from './api/Collector';
@@ -75,6 +75,16 @@ function configureTraceKit(options: ParsedStackOptions) {
   anyObj.linesOfContext = beforeAfterMax * 2 + 1;
 }
 
+/**
+ * Check if the client supports LDClientLogging.
+ *
+ * @param client The client to check.
+ * @returns True if the client is an instance of LDClientLogging.
+ */
+function isLDClientLogging(client: unknown): client is LDClientLogging {
+  return (client as any).logger !== undefined;
+}
+
 export default class BrowserTelemetryImpl implements BrowserTelemetry {
   private _maxPendingEvents: number;
   private _maxBreadcrumbs: number;
@@ -159,8 +169,13 @@ export default class BrowserTelemetryImpl implements BrowserTelemetry {
   }
 
   private _setLogger() {
-    this._logger =
-      this._options.logger ?? ((this._client as any)?.logger as MinLogger) ?? fallbackLogger;
+    if (this._options.logger) {
+      this._logger = this._options.logger;
+    } else if (isLDClientLogging(this._client)) {
+      this._logger = this._client.logger;
+    } else {
+      this._logger = fallbackLogger;
+    }
   }
 
   inspectors(): LDInspection[] {

packages/telemetry/browser-telemetry/src/api/client/LDClientLogging.ts

@@ -0,0 +1,8 @@
+import { MinLogger } from '../MinLogger';
+
+/**
+ * Minimal client interface which allows for loggng. Works with 4.x and higher versions of the javascript client.
+ */
+export interface LDClientLogging {
+  readonly logger: MinLogger;
+}

packages/telemetry/browser-telemetry/src/api/client/index.ts

@@ -1 +1,2 @@
 export * from './LDClientTracking';
+export * from './LDClientLogging';