feat: Add support for getting the logger from server-side SDKs. (#684)

Author: kinyoklion

packages/shared/sdk-server/__tests__/LDClientImpl.test.ts

@@ -259,4 +259,17 @@ describe('LDClientImpl', () => {
     await client.waitForInitialization({ timeout: Number.MAX_SAFE_INTEGER });
     expect(logger.getCount(LogLevel.Warn)).toBe(0);
   });
+
+  it('provides access to the underlying logger', async () => {
+    const logger = new TestLogger();
+    client = createClient({ logger, offline: true });
+    client.logger?.error('this is an error');
+    expect(logger.getCount(LogLevel.Error)).toBe(1);
+    logger.expectMessages([
+      {
+        level: LogLevel.Error,
+        matches: /this is an error/,
+      },
+    ]);
+  });
 });

packages/shared/sdk-server/src/LDClientImpl.ts

@@ -128,6 +128,10 @@ export default class LDClientImpl implements LDClient {
 
   private _hookRunner: HookRunner;
 
+  public get logger(): LDLogger | undefined {
+    return this._logger;
+  }
+
   /**
    * Intended for use by platform specific client implementations.
    *

packages/shared/sdk-server/src/api/LDClient.ts

@@ -3,6 +3,7 @@ import {
   LDEvaluationDetail,
   LDEvaluationDetailTyped,
   LDFlagValue,
+  LDLogger,
 } from '@launchdarkly/js-sdk-common';
 
 import { LDMigrationOpEvent, LDMigrationVariation } from './data';
@@ -461,4 +462,11 @@ export interface LDClient {
    * @param Hook The hook to add.
    */
   addHook?(hook: Hook): void;
+
+  /**
+   * Get the logger used by this LDClient instance.
+   *
+   * For all platforms that support logging the logger should be present.
+   */
+  get logger(): LDLogger | undefined;
 }