From a0901700ff04c0a26b526e3210b05ecf10d24736 Mon Sep 17 00:00:00 2001
From: Ryan Lamb <4955475+kinyoklion@users.noreply.github.com>
Date: Thu, 19 May 2022 16:26:36 -0700
Subject: [PATCH 1/7] Work on initial scaffold.

---
 .../src/BigSegmentsStoreStatusProviderNode.ts |  26 +++++
 platform-node/src/LDClientNode.ts             |  96 +++++++++++++++
 platform-node/src/api/LDClient.ts             |  22 ++++
 platform-node/src/api/index.ts                |   2 +
 .../BigSegmentStoreStatusProvider.ts          |   8 +-
 platform-node/src/api/interfaces/index.ts     |   1 +
 platform-node/src/index.ts                    |  25 +---
 .../src/{ => platform}/NodeCrypto.ts          |   0
 .../src/{ => platform}/NodeFilesystem.ts      |   0
 platform-node/src/{ => platform}/NodeInfo.ts  |   2 +-
 .../src/{ => platform}/NodePlatform.ts        |   0
 .../src/{ => platform}/NodeRequests.ts        |   0
 .../src/{ => platform}/NodeResponse.ts        |   0
 .../src/BigSegmentStatusProvider.ts           |  36 ++++++
 server-sdk-common/src/LDClientImpl.ts         | 109 ++++++++++++++++++
 server-sdk-common/src/api/LDClient.ts         |  45 +-------
 server-sdk-common/src/api/interfaces/index.ts |   1 -
 server-sdk-common/src/index.ts                |   4 +
 18 files changed, 304 insertions(+), 73 deletions(-)
 create mode 100644 platform-node/src/BigSegmentsStoreStatusProviderNode.ts
 create mode 100644 platform-node/src/LDClientNode.ts
 create mode 100644 platform-node/src/api/LDClient.ts
 create mode 100644 platform-node/src/api/index.ts
 rename {server-sdk-common => platform-node}/src/api/interfaces/BigSegmentStoreStatusProvider.ts (86%)
 create mode 100644 platform-node/src/api/interfaces/index.ts
 rename platform-node/src/{ => platform}/NodeCrypto.ts (100%)
 rename platform-node/src/{ => platform}/NodeFilesystem.ts (100%)
 rename platform-node/src/{ => platform}/NodeInfo.ts (94%)
 rename platform-node/src/{ => platform}/NodePlatform.ts (100%)
 rename platform-node/src/{ => platform}/NodeRequests.ts (100%)
 rename platform-node/src/{ => platform}/NodeResponse.ts (100%)
 create mode 100644 server-sdk-common/src/BigSegmentStatusProvider.ts
 create mode 100644 server-sdk-common/src/LDClientImpl.ts

diff --git a/platform-node/src/BigSegmentsStoreStatusProviderNode.ts b/platform-node/src/BigSegmentsStoreStatusProviderNode.ts
new file mode 100644
index 0000000000..0a4b03cd5c
--- /dev/null
+++ b/platform-node/src/BigSegmentsStoreStatusProviderNode.ts
@@ -0,0 +1,26 @@
+import { LDClientImpl } from '@launchdarkly/js-server-sdk-common';
+import { BigSegmentStoreStatus } from '@launchdarkly/js-server-sdk-common/dist/api/interfaces';
+import EventEmitter from 'events';
+import { BigSegmentStoreStatusProvider } from './api/interfaces/BigSegmentStoreStatusProvider';
+
+export default class BigSegmentStoreStatusProviderNode
+  extends EventEmitter implements BigSegmentStoreStatusProvider {
+  clientBase: LDClientImpl;
+
+  constructor(clientBase: LDClientImpl) {
+    super();
+    this.clientBase = clientBase;
+
+    clientBase.bigSegmentStoreStatusProvider.setStatusHandler((status) => {
+      this.emit('change', status);
+    });
+  }
+
+  getStatus(): BigSegmentStoreStatus | undefined {
+    return this.clientBase.bigSegmentStoreStatusProvider.getStatus();
+  }
+
+  requireStatus(): Promise<BigSegmentStoreStatus> {
+    return this.clientBase.bigSegmentStoreStatusProvider.requireStatus();
+  }
+}
diff --git a/platform-node/src/LDClientNode.ts b/platform-node/src/LDClientNode.ts
new file mode 100644
index 0000000000..b34d16660f
--- /dev/null
+++ b/platform-node/src/LDClientNode.ts
@@ -0,0 +1,96 @@
+/* eslint-disable @typescript-eslint/no-unused-vars */
+/* eslint-disable class-methods-use-this */
+import {
+  LDClientImpl, LDContext, LDEvaluationDetail, LDFlagsState, LDFlagsStateOptions, LDOptions,
+} from '@launchdarkly/js-server-sdk-common';
+
+import EventEmitter from 'events';
+import { LDClient } from './api/LDClient';
+import BigSegmentStoreStatusProviderNode from './BigSegmentsStoreStatusProviderNode';
+import { BigSegmentStoreStatusProvider } from './api/interfaces/BigSegmentStoreStatusProvider';
+import NodePlatform from './platform/NodePlatform';
+
+export default class LDClientNode extends EventEmitter implements LDClient {
+  /**
+   * The LDClientImpl is included through composition, instead of inheritance,
+   * for a couple of reasons.
+   * 1. This allows the node client to implement EventEmitter, where otherwise
+   * it would be unable to from single inheritance. EventEmitter is not included
+   * in common because it is node specific.
+   *
+   * 2. This allows conversions of some types compared to the base implementation.
+   * Such as returning a node `LDClient` instead of the base `LDClient` interface.
+   * This interface extends EventEmitter to support #1.
+   */
+  private client: LDClientImpl;
+
+  constructor(options: LDOptions) {
+    super();
+    // TODO: Remember to parse the options before providing them to the platform.
+    this.client = new LDClientImpl(new NodePlatform(options));
+    // Extend the BigSegmentStoreStatusProvider from the common client to allow
+    // for use of the event emitter.
+    this.bigSegmentStoreStatusProvider = new BigSegmentStoreStatusProviderNode(this.client);
+  }
+
+  bigSegmentStoreStatusProvider: BigSegmentStoreStatusProvider;
+
+  initialized(): boolean {
+    return this.client.initialized();
+  }
+
+  async waitForInitialization(): Promise<LDClient> {
+    await this.client.waitForInitialization();
+    return this;
+  }
+
+  variation(
+    key: string,
+    context: LDContext,
+    defaultValue: any,
+    callback?: (err: any, res: any) => void,
+  ): Promise<any> {
+    return this.client.variation(key, context, defaultValue, callback);
+  }
+
+  variationDetail(
+    key: string,
+    context: LDContext,
+    defaultValue: any,
+    callback?: (err: any, res: LDEvaluationDetail) => void,
+  ): Promise<LDEvaluationDetail> {
+    return this.client.variationDetail(key, context, defaultValue, callback);
+  }
+
+  allFlagsState(
+    context: LDContext,
+    options?: LDFlagsStateOptions,
+    callback?: (err: Error, res: LDFlagsState) => void,
+  ): Promise<LDFlagsState> {
+    return this.client.allFlagsState(context, options, callback);
+  }
+
+  secureModeHash(context: LDContext): string {
+    return this.client.secureModeHash(context);
+  }
+
+  close(): void {
+    this.client.close();
+  }
+
+  isOffline(): boolean {
+    return this.client.isOffline();
+  }
+
+  track(key: string, context: LDContext, data?: any, metricValue?: number): void {
+    return this.client.track(key, context, data, metricValue);
+  }
+
+  identify(context: LDContext): void {
+    return this.client.identify(context);
+  }
+
+  flush(callback?: (err: Error, res: boolean) => void): Promise<void> {
+    return this.client.flush(callback);
+  }
+}
diff --git a/platform-node/src/api/LDClient.ts b/platform-node/src/api/LDClient.ts
new file mode 100644
index 0000000000..e36c8d94c7
--- /dev/null
+++ b/platform-node/src/api/LDClient.ts
@@ -0,0 +1,22 @@
+import { LDClient as LDClientCommon } from '@launchdarkly/js-server-sdk-common';
+import EventEmitter from 'events';
+import { BigSegmentStoreStatusProvider } from './interfaces/BigSegmentStoreStatusProvider';
+
+/**
+ * The LaunchDarkly SDK client object.
+ *
+ * Create this object with [[init]]. Applications should configure the client at startup time and
+ * continue to use it throughout the lifetime of the application, rather than creating instances on
+ * the fly.
+ *
+ */
+export interface LDClient extends LDClientCommon, EventEmitter {
+  /**
+   * A mechanism for tracking the status of a Big Segment store.
+   *
+   * This object has methods for checking whether the Big Segment store is (as far as the SDK
+   * knows) currently operational and tracking changes in this status. See
+   * {@link interfaces.BigSegmentStoreStatusProvider} for more about this functionality.
+   */
+  readonly bigSegmentStoreStatusProvider: BigSegmentStoreStatusProvider;
+}
diff --git a/platform-node/src/api/index.ts b/platform-node/src/api/index.ts
new file mode 100644
index 0000000000..5ace2345c0
--- /dev/null
+++ b/platform-node/src/api/index.ts
@@ -0,0 +1,2 @@
+export * from './LDClient';
+export * from './interfaces';
diff --git a/server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider.ts b/platform-node/src/api/interfaces/BigSegmentStoreStatusProvider.ts
similarity index 86%
rename from server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider.ts
rename to platform-node/src/api/interfaces/BigSegmentStoreStatusProvider.ts
index 45a512db30..0ae8846d8a 100644
--- a/server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider.ts
+++ b/platform-node/src/api/interfaces/BigSegmentStoreStatusProvider.ts
@@ -1,5 +1,5 @@
-import { EventEmitter } from 'events';
-import { BigSegmentStoreStatus } from './BigSegmentStoreStatus';
+import EventEmitter from 'events';
+import { interfaces } from '@launchdarkly/js-server-sdk-common';
 
 /**
  * An interface for querying the status of a Big Segment store.
@@ -27,12 +27,12 @@ export interface BigSegmentStoreStatusProvider extends EventEmitter {
    * @returns a {@link BigSegmentStoreStatus}, or `undefined` if the SDK has not yet queried the
    *   Big Segment store status
    */
-  getStatus(): BigSegmentStoreStatus | undefined;
+  getStatus(): interfaces.BigSegmentStoreStatus | undefined;
 
   /**
    * Gets the current status of the store, querying it if the status has not already been queried.
    *
    * @returns a Promise for the status of the store
    */
-  requireStatus(): Promise<BigSegmentStoreStatus>;
+  requireStatus(): Promise<interfaces.BigSegmentStoreStatus>;
 }
diff --git a/platform-node/src/api/interfaces/index.ts b/platform-node/src/api/interfaces/index.ts
new file mode 100644
index 0000000000..aaf6c352a2
--- /dev/null
+++ b/platform-node/src/api/interfaces/index.ts
@@ -0,0 +1 @@
+export * from './BigSegmentStoreStatusProvider';
\ No newline at end of file
diff --git a/platform-node/src/index.ts b/platform-node/src/index.ts
index 897f20d7d7..0567f419eb 100644
--- a/platform-node/src/index.ts
+++ b/platform-node/src/index.ts
@@ -1,24 +1,3 @@
-/* eslint-disable no-console */
-// This file contains temporary code for testing.
-import NodePlatform from './NodePlatform';
+export * from '@launchdarkly/js-server-sdk-common';
 
-const platform = new NodePlatform({
-  tlsParams: {
-    checkServerIdentity: (name) => {
-      console.log('GOT A IDENTITY CHECK', name);
-      return undefined;
-    },
-  },
-});
-
-async function runTest() {
-  console.log('Making request');
-  const res = await platform.requests.fetch('https://www.google.com');
-  console.log('Got res', res);
-  const body = await res.text();
-  console.log('Body', body);
-}
-
-runTest();
-
-console.log(platform.info.sdkData());
+export { LDClient } from './api';
diff --git a/platform-node/src/NodeCrypto.ts b/platform-node/src/platform/NodeCrypto.ts
similarity index 100%
rename from platform-node/src/NodeCrypto.ts
rename to platform-node/src/platform/NodeCrypto.ts
diff --git a/platform-node/src/NodeFilesystem.ts b/platform-node/src/platform/NodeFilesystem.ts
similarity index 100%
rename from platform-node/src/NodeFilesystem.ts
rename to platform-node/src/platform/NodeFilesystem.ts
diff --git a/platform-node/src/NodeInfo.ts b/platform-node/src/platform/NodeInfo.ts
similarity index 94%
rename from platform-node/src/NodeInfo.ts
rename to platform-node/src/platform/NodeInfo.ts
index 72ee63aeab..03d9e198ca 100644
--- a/platform-node/src/NodeInfo.ts
+++ b/platform-node/src/platform/NodeInfo.ts
@@ -4,7 +4,7 @@ import { PlatformData, SdkData } from '@launchdarkly/js-server-sdk-common/dist/p
 
 import * as os from 'os';
 
-import * as packageJson from '../package.json';
+import * as packageJson from '../../package.json';
 
 function processPlatformName(name: string): string {
   switch (name) {
diff --git a/platform-node/src/NodePlatform.ts b/platform-node/src/platform/NodePlatform.ts
similarity index 100%
rename from platform-node/src/NodePlatform.ts
rename to platform-node/src/platform/NodePlatform.ts
diff --git a/platform-node/src/NodeRequests.ts b/platform-node/src/platform/NodeRequests.ts
similarity index 100%
rename from platform-node/src/NodeRequests.ts
rename to platform-node/src/platform/NodeRequests.ts
diff --git a/platform-node/src/NodeResponse.ts b/platform-node/src/platform/NodeResponse.ts
similarity index 100%
rename from platform-node/src/NodeResponse.ts
rename to platform-node/src/platform/NodeResponse.ts
diff --git a/server-sdk-common/src/BigSegmentStatusProvider.ts b/server-sdk-common/src/BigSegmentStatusProvider.ts
new file mode 100644
index 0000000000..3bf42038ae
--- /dev/null
+++ b/server-sdk-common/src/BigSegmentStatusProvider.ts
@@ -0,0 +1,36 @@
+/* eslint-disable class-methods-use-this */
+import { BigSegmentStoreStatus } from './api/interfaces';
+
+type StatusHandler = (status: BigSegmentStoreStatus) => void;
+
+export default class BigSegmentStoreStatusProvider {
+  private onStatus?: StatusHandler;
+
+  /**
+   * Gets the current status of the store, if known.
+   *
+   * @returns a {@link BigSegmentStoreStatus}, or `undefined` if the SDK has not yet queried the
+   *   Big Segment store status
+   */
+  getStatus(): BigSegmentStoreStatus | undefined {
+    return undefined;
+  }
+
+  /**
+   * Gets the current status of the store, querying it if the status has not already been queried.
+   *
+   * @returns a Promise for the status of the store
+   */
+  async requireStatus(): Promise<BigSegmentStoreStatus> {
+    return Promise.reject();
+  }
+
+  /**
+   * Set the status handler. Only one handler can be registered and this will replace the existing
+   * handler.
+   * @param handler
+   */
+  setStatusHandler(handler: StatusHandler) {
+    this.onStatus = handler;
+  }
+}
diff --git a/server-sdk-common/src/LDClientImpl.ts b/server-sdk-common/src/LDClientImpl.ts
new file mode 100644
index 0000000000..27d1b92050
--- /dev/null
+++ b/server-sdk-common/src/LDClientImpl.ts
@@ -0,0 +1,109 @@
+/* eslint-disable @typescript-eslint/no-unused-vars */
+/* eslint-disable class-methods-use-this */
+import {
+  LDClient, LDContext, LDEvaluationDetail, LDFlagsState, LDFlagsStateOptions,
+} from './api';
+import BigSegmentStoreStatusProvider from './BigSegmentStatusProvider';
+import { Platform } from './platform';
+
+enum EventTypes {
+  /**
+   * Emitted on errors other than a failure to initialize.
+   */
+  Error = 'error',
+  /**
+   * Emitted when the SDK fails to initialize.
+   */
+  Failed = 'failed',
+  /**
+   * Emitted when the SDK is ready to use.
+   */
+  Ready = 'ready',
+}
+
+enum InitState {
+  Initializing,
+  Initialized,
+  Failed,
+}
+
+export default class LDClientImpl implements LDClient {
+  private platform: Platform;
+
+  private initState: InitState = InitState.Initializing;
+
+  /**
+   * Intended for use by platform specific client implementations.
+   *
+   * It is not included in the main interface because it requires the use of
+   * a platform event system. For node this would be an EventEmitter, for other
+   * platforms it would likely be an EventTarget.
+   */
+  public bigSegmentStoreStatusProvider = new BigSegmentStoreStatusProvider();
+
+  constructor(targetPlatform: Platform) {
+    this.platform = targetPlatform;
+  }
+
+  initialized(): boolean {
+    return this.initState === InitState.Initialized;
+  }
+
+  waitForInitialization(): Promise<LDClient> {
+    throw new Error('Method not implemented.');
+  }
+
+  variation(
+    key: string,
+    context: LDContext,
+    defaultValue: any,
+    callback?: (err: any, res: any) => void,
+  ): Promise<any> {
+    throw new Error('Method not implemented.');
+  }
+
+  variationDetail(
+    key: string,
+    context: LDContext,
+    defaultValue: any,
+    callback?: (err: any, res: LDEvaluationDetail) => void,
+  ): Promise<LDEvaluationDetail> {
+    throw new Error('Method not implemented.');
+  }
+
+  allFlagsState(
+    context: LDContext,
+    options?: LDFlagsStateOptions,
+    callback?: (err: Error, res: LDFlagsState) => void,
+  ): Promise<LDFlagsState> {
+    throw new Error('Method not implemented.');
+  }
+
+  secureModeHash(context: LDContext): string {
+    throw new Error('Method not implemented.');
+  }
+
+  close(): void {
+    throw new Error('Method not implemented.');
+  }
+
+  isOffline(): boolean {
+    throw new Error('Method not implemented.');
+  }
+
+  track(key: string, context: LDContext, data?: any, metricValue?: number): void {
+    throw new Error('Method not implemented.');
+  }
+
+  identify(context: LDContext): void {
+    throw new Error('Method not implemented.');
+  }
+
+  flush(callback?: (err: Error, res: boolean) => void): Promise<void> {
+    throw new Error('Method not implemented.');
+  }
+
+  on(event: string | symbol, listener: (...args: any[]) => void): this {
+    throw new Error('Method not implemented.');
+  }
+}
diff --git a/server-sdk-common/src/api/LDClient.ts b/server-sdk-common/src/api/LDClient.ts
index 6a53d11fa4..ada8704a04 100644
--- a/server-sdk-common/src/api/LDClient.ts
+++ b/server-sdk-common/src/api/LDClient.ts
@@ -1,6 +1,4 @@
-import { EventEmitter } from 'events';
 import { LDContext } from './LDContext';
-import { BigSegmentStoreStatusProvider } from './interfaces/BigSegmentStoreStatusProvider';
 import { LDEvaluationDetail } from './data/LDEvaluationDetail';
 import { LDFlagsState } from './data/LDFlagsState';
 import { LDFlagsStateOptions } from './data/LDFlagsStateOptions';
@@ -13,15 +11,8 @@ import { LDFlagValue } from './data/LDFlagValue';
  * continue to use it throughout the lifetime of the application, rather than creating instances on
  * the fly.
  *
- * Note that `LDClient` inherits from `EventEmitter`, so you can use the standard `on()`, `once()`,
- * and `off()` methods to receive events. The standard `EventEmitter` methods are not documented
- * here; see the
- * {@link https://nodejs.org/api/events.html#events_class_eventemitter|Node API documentation}. For
- * a description of events you can listen for, see [[on]].
- *
- * @see {@link https://docs.launchdarkly.com/sdk/server-side/node-js|SDK Reference Guide}
  */
-export interface LDClient extends EventEmitter {
+export interface LDClient {
   /**
    * Tests whether the client has completed initialization.
    *
@@ -241,23 +232,9 @@ export interface LDClient extends EventEmitter {
    */
   flush(callback?: (err: Error, res: boolean) => void): Promise<void>;
 
-  /**
-   * A mechanism for tracking the status of a Big Segment store.
-   *
-   * This object has methods for checking whether the Big Segment store is (as far as the SDK
-   * knows) currently operational and tracking changes in this status. See
-   * {@link interfaces.BigSegmentStoreStatusProvider} for more about this functionality.
-   */
-  readonly bigSegmentStoreStatusProvider: BigSegmentStoreStatusProvider;
-
   /**
    * Registers an event listener that will be called when the client triggers some type of event.
    *
-   * This is the standard `on` method inherited from Node's `EventEmitter`; see the
-   * {@link https://nodejs.org/api/events.html#events_class_eventemitter|Node API docs} for more
-   * details on how to manage event listeners. Here is a description of the event types defined by
-   * `LDClient`.
-   *
    * - `"ready"`: Sent only once, when the client has successfully connected to LaunchDarkly.
    *   Alternately, you can detect this with [[waitForInitialization]].
    * - `"failed"`: Sent only once, if the client has permanently failed to connect to LaunchDarkly.
@@ -275,24 +252,4 @@ export interface LDClient extends EventEmitter {
    * @param listener the function to call when the event happens
    */
   on(event: string | symbol, listener: (...args: any[]) => void): this;
-
-  // The following are symbols that LDClient inherits from EventEmitter, which we are declaring
-  // again here only so that we can use @ignore to exclude them from the generated docs.
-  // Unfortunately it does not seem possible to exclude these inherited methods en masse without
-  // using a Typedoc plugin.
-  /** @ignore */ addListener(event: string | symbol, listener: (...args: any[]) => void): this;
-  /** @ignore */ emit(event: string | symbol, ...args: any[]): boolean;
-  /** @ignore */ eventNames(): Array<string | symbol>;
-  /** @ignore */ getMaxListeners(): number;
-  /** @ignore */ listenerCount(type: string | symbol): number;
-  /** @ignore */ listeners(event: string | symbol): Function[];
-  /** @ignore */ prependListener(event: string | symbol, listener: (...args: any[]) => void): this;
-  /** @ignore */ prependOnceListener(event: string | symbol, listener:
-  (...args: any[]) => void): this;
-  /** @ignore */ rawListeners(event: string | symbol): Function[];
-  /** @ignore */ removeAllListeners(event?: string | symbol): this;
-  /** @ignore */ removeListener(event: string | symbol, listener: (...args: any[]) => void): this;
-  /** @ignore */ setMaxListeners(n: number): this;
-  /** @ignore */ once(event: string | symbol, listener: (...args: any[]) => void): this;
-  /** @ignore */ off(event: string | symbol, listener: (...args: any[]) => void): this;
 }
diff --git a/server-sdk-common/src/api/interfaces/index.ts b/server-sdk-common/src/api/interfaces/index.ts
index 827cee6e7b..1a4a141cde 100644
--- a/server-sdk-common/src/api/interfaces/index.ts
+++ b/server-sdk-common/src/api/interfaces/index.ts
@@ -2,7 +2,6 @@ export * from './BigSegmentStore';
 export * from './BigSegmentStoreMembership';
 export * from './BigSegmentStoreMetadata';
 export * from './BigSegmentStoreStatus';
-export * from './BigSegmentStoreStatusProvider';
 export * from './DataCollection';
 export * from './DataKind';
 export * from './FullDataSet';
diff --git a/server-sdk-common/src/index.ts b/server-sdk-common/src/index.ts
index e349fcd5f6..2a3603259f 100644
--- a/server-sdk-common/src/index.ts
+++ b/server-sdk-common/src/index.ts
@@ -1,2 +1,6 @@
+import LDClientImpl from './LDClientImpl';
+
 export * as platform from './platform';
 export * from './api';
+
+export { LDClientImpl };

From 0b470eab6d55b529f666bbd953458bb632c0c35e Mon Sep 17 00:00:00 2001
From: Ryan Lamb <4955475+kinyoklion@users.noreply.github.com>
Date: Thu, 19 May 2022 16:31:17 -0700
Subject: [PATCH 2/7] Update index exports.

---
 platform-node/src/index.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/platform-node/src/index.ts b/platform-node/src/index.ts
index 0567f419eb..c1fecbeeab 100644
--- a/platform-node/src/index.ts
+++ b/platform-node/src/index.ts
@@ -1,3 +1,9 @@
+import LDClientImpl from './LDClientNode';
+
 export * from '@launchdarkly/js-server-sdk-common';
 
-export { LDClient } from './api';
+// To replace the exports from `export *` we need to name them.
+// So the below exports replace them with the Node specific variants.
+
+export { LDClient, BigSegmentStoreStatusProvider } from './api';
+export { LDClientImpl };

From 93fbac63cf6625d2e03a719c4023aa0a2458ec2c Mon Sep 17 00:00:00 2001
From: Ryan Lamb <4955475+kinyoklion@users.noreply.github.com>
Date: Thu, 19 May 2022 16:39:43 -0700
Subject: [PATCH 3/7] Add an extra blank line.

---
 platform-node/src/api/interfaces/index.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/platform-node/src/api/interfaces/index.ts b/platform-node/src/api/interfaces/index.ts
index aaf6c352a2..153474b58c 100644
--- a/platform-node/src/api/interfaces/index.ts
+++ b/platform-node/src/api/interfaces/index.ts
@@ -1 +1 @@
-export * from './BigSegmentStoreStatusProvider';
\ No newline at end of file
+export * from './BigSegmentStoreStatusProvider';

From 8be08daaa960319bae0285db3ed629b4b3ab1267 Mon Sep 17 00:00:00 2001
From: Ryan Lamb <4955475+kinyoklion@users.noreply.github.com>
Date: Mon, 23 May 2022 10:20:03 -0700
Subject: [PATCH 4/7] Attempt using mixin for event emitter.

---
 platform-node/__tests__/NodeInfo_test.ts      |  2 +-
 platform-node/__tests__/NodeRequests_test.ts  |  2 +-
 .../src/BigSegmentsStoreStatusProviderNode.ts | 29 ++----
 platform-node/src/Emits.ts                    | 74 ++++++++++++++
 platform-node/src/LDClientNode.ts             | 97 +++----------------
 platform-node/src/api/LDClient.ts             |  6 +-
 ...rovider.ts => BigSegmentStatusProvider.ts} |  2 +-
 platform-node/src/api/interfaces/index.ts     |  2 +-
 platform-node/src/index.ts                    |  5 +-
 ...der.ts => BigSegmentStatusProviderImpl.ts} |  6 +-
 server-sdk-common/src/LDClientImpl.ts         |  4 +-
 .../BigSegmentStoreStatusProvider.ts          | 30 ++++++
 server-sdk-common/src/api/interfaces/index.ts |  1 +
 server-sdk-common/src/index.ts                |  2 +
 14 files changed, 141 insertions(+), 121 deletions(-)
 create mode 100644 platform-node/src/Emits.ts
 rename platform-node/src/api/interfaces/{BigSegmentStoreStatusProvider.ts => BigSegmentStatusProvider.ts} (95%)
 rename server-sdk-common/src/{BigSegmentStatusProvider.ts => BigSegmentStatusProviderImpl.ts} (78%)
 create mode 100644 server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider.ts

diff --git a/platform-node/__tests__/NodeInfo_test.ts b/platform-node/__tests__/NodeInfo_test.ts
index 18c527e4ba..0567413c76 100644
--- a/platform-node/__tests__/NodeInfo_test.ts
+++ b/platform-node/__tests__/NodeInfo_test.ts
@@ -1,5 +1,5 @@
 import * as os from 'os';
-import NodeInfo from '../src/NodeInfo';
+import NodeInfo from '../src/platform/NodeInfo';
 
 describe('given an information instance', () => {
   const info = new NodeInfo();
diff --git a/platform-node/__tests__/NodeRequests_test.ts b/platform-node/__tests__/NodeRequests_test.ts
index bf21e2358e..4cdb820811 100644
--- a/platform-node/__tests__/NodeRequests_test.ts
+++ b/platform-node/__tests__/NodeRequests_test.ts
@@ -1,6 +1,6 @@
 import * as http from 'http';
 
-import NodeRequests from '../src/NodeRequests';
+import NodeRequests from '../src/platform/NodeRequests';
 
 const PORT = '3000';
 const TEXT_RESPONSE = 'Test Text';
diff --git a/platform-node/src/BigSegmentsStoreStatusProviderNode.ts b/platform-node/src/BigSegmentsStoreStatusProviderNode.ts
index 0a4b03cd5c..24ccdc61fa 100644
--- a/platform-node/src/BigSegmentsStoreStatusProviderNode.ts
+++ b/platform-node/src/BigSegmentsStoreStatusProviderNode.ts
@@ -1,26 +1,9 @@
-import { LDClientImpl } from '@launchdarkly/js-server-sdk-common';
-import { BigSegmentStoreStatus } from '@launchdarkly/js-server-sdk-common/dist/api/interfaces';
+import { BigSegmentStoreStatusProviderImpl } from '@launchdarkly/js-server-sdk-common';
 import EventEmitter from 'events';
-import { BigSegmentStoreStatusProvider } from './api/interfaces/BigSegmentStoreStatusProvider';
+import { Emits } from './Emits';
 
-export default class BigSegmentStoreStatusProviderNode
-  extends EventEmitter implements BigSegmentStoreStatusProvider {
-  clientBase: LDClientImpl;
-
-  constructor(clientBase: LDClientImpl) {
-    super();
-    this.clientBase = clientBase;
-
-    clientBase.bigSegmentStoreStatusProvider.setStatusHandler((status) => {
-      this.emit('change', status);
-    });
-  }
-
-  getStatus(): BigSegmentStoreStatus | undefined {
-    return this.clientBase.bigSegmentStoreStatusProvider.getStatus();
-  }
-
-  requireStatus(): Promise<BigSegmentStoreStatus> {
-    return this.clientBase.bigSegmentStoreStatusProvider.requireStatus();
-  }
+class BigSegmentStoreStatusProviderNode extends BigSegmentStoreStatusProviderImpl {
+  emitter: EventEmitter = new EventEmitter();
 }
+
+export default Emits(BigSegmentStoreStatusProviderNode);
diff --git a/platform-node/src/Emits.ts b/platform-node/src/Emits.ts
new file mode 100644
index 0000000000..57addc03f9
--- /dev/null
+++ b/platform-node/src/Emits.ts
@@ -0,0 +1,74 @@
+import EventEmitter from 'events';
+
+export type EventableConstructor<T = {}> = new (...args: any[]) => T;
+export type Eventable = EventableConstructor<{ emitter: EventEmitter }>;
+
+export function Emits<TBase extends Eventable>(Base: TBase) {
+  return class WithEvents extends Base {
+    addListener(eventName: string | symbol, listener: (...args: any[]) => void): this {
+      this.emitter.addListener(eventName, listener);
+      return this;
+    }
+
+    once(eventName: string | symbol, listener: (...args: any[]) => void): this {
+      this.emitter.once(eventName, listener);
+      return this;
+    }
+
+    removeListener(eventName: string | symbol, listener: (
+      ...args: any[]) => void): this {
+      this.emitter.removeListener(eventName, listener);
+      return this;
+    }
+
+    off(eventName: string | symbol, listener: (...args: any) => void): this {
+      this.emitter.off(eventName, listener);
+      return this;
+    }
+
+    removeAllListeners(event?: string | symbol): this {
+      this.emitter.removeAllListeners(event);
+      return this;
+    }
+
+    setMaxListeners(n: number): this {
+      this.emitter.setMaxListeners(n);
+      return this;
+    }
+
+    getMaxListeners(): number {
+      return this.emitter.getMaxListeners();
+    }
+
+    listeners(eventName: string | symbol): Function[] {
+      return this.emitter.listeners(eventName);
+    }
+
+    rawListeners(eventName: string | symbol): Function[] {
+      return this.emitter.rawListeners(eventName);
+    }
+
+    emit(eventName: string | symbol, ...args: any[]): boolean {
+      return this.emitter.emit(eventName, args);
+    }
+
+    listenerCount(eventName: string | symbol): number {
+      return this.emitter.listenerCount(eventName);
+    }
+
+    prependListener(eventName: string | symbol, listener: (
+      ...args: any[]) => void): this {
+      this.emitter.prependListener(eventName, listener);
+      return this;
+    }
+
+    prependOnceListener(eventName: string | symbol, listener: (...args: any[]) => void): this {
+      this.emitter.prependOnceListener(eventName, listener);
+      return this;
+    }
+
+    eventNames(): (string | symbol)[] {
+      return this.emitter.eventNames();
+    }
+  };
+}
\ No newline at end of file
diff --git a/platform-node/src/LDClientNode.ts b/platform-node/src/LDClientNode.ts
index b34d16660f..6204e6cfb0 100644
--- a/platform-node/src/LDClientNode.ts
+++ b/platform-node/src/LDClientNode.ts
@@ -1,96 +1,25 @@
 /* eslint-disable @typescript-eslint/no-unused-vars */
 /* eslint-disable class-methods-use-this */
+// eslint-disable-next-line max-classes-per-file
 import {
-  LDClientImpl, LDContext, LDEvaluationDetail, LDFlagsState, LDFlagsStateOptions, LDOptions,
+  LDClientImpl, LDOptions,
 } from '@launchdarkly/js-server-sdk-common';
 
 import EventEmitter from 'events';
-import { LDClient } from './api/LDClient';
-import BigSegmentStoreStatusProviderNode from './BigSegmentsStoreStatusProviderNode';
-import { BigSegmentStoreStatusProvider } from './api/interfaces/BigSegmentStoreStatusProvider';
 import NodePlatform from './platform/NodePlatform';
+import { Emits } from './Emits';
+import BigSegmentStoreStatusProviderNode from './BigSegmentsStoreStatusProviderNode';
 
-export default class LDClientNode extends EventEmitter implements LDClient {
-  /**
-   * The LDClientImpl is included through composition, instead of inheritance,
-   * for a couple of reasons.
-   * 1. This allows the node client to implement EventEmitter, where otherwise
-   * it would be unable to from single inheritance. EventEmitter is not included
-   * in common because it is node specific.
-   *
-   * 2. This allows conversions of some types compared to the base implementation.
-   * Such as returning a node `LDClient` instead of the base `LDClient` interface.
-   * This interface extends EventEmitter to support #1.
-   */
-  private client: LDClientImpl;
-
-  constructor(options: LDOptions) {
-    super();
-    // TODO: Remember to parse the options before providing them to the platform.
-    this.client = new LDClientImpl(new NodePlatform(options));
-    // Extend the BigSegmentStoreStatusProvider from the common client to allow
-    // for use of the event emitter.
-    this.bigSegmentStoreStatusProvider = new BigSegmentStoreStatusProviderNode(this.client);
-  }
-
-  bigSegmentStoreStatusProvider: BigSegmentStoreStatusProvider;
-
-  initialized(): boolean {
-    return this.client.initialized();
-  }
-
-  async waitForInitialization(): Promise<LDClient> {
-    await this.client.waitForInitialization();
-    return this;
-  }
-
-  variation(
-    key: string,
-    context: LDContext,
-    defaultValue: any,
-    callback?: (err: any, res: any) => void,
-  ): Promise<any> {
-    return this.client.variation(key, context, defaultValue, callback);
-  }
-
-  variationDetail(
-    key: string,
-    context: LDContext,
-    defaultValue: any,
-    callback?: (err: any, res: LDEvaluationDetail) => void,
-  ): Promise<LDEvaluationDetail> {
-    return this.client.variationDetail(key, context, defaultValue, callback);
-  }
-
-  allFlagsState(
-    context: LDContext,
-    options?: LDFlagsStateOptions,
-    callback?: (err: Error, res: LDFlagsState) => void,
-  ): Promise<LDFlagsState> {
-    return this.client.allFlagsState(context, options, callback);
-  }
-
-  secureModeHash(context: LDContext): string {
-    return this.client.secureModeHash(context);
-  }
-
-  close(): void {
-    this.client.close();
-  }
-
-  isOffline(): boolean {
-    return this.client.isOffline();
-  }
-
-  track(key: string, context: LDContext, data?: any, metricValue?: number): void {
-    return this.client.track(key, context, data, metricValue);
-  }
+class LDClientNode extends LDClientImpl {
+  emitter: EventEmitter = new EventEmitter();
 
-  identify(context: LDContext): void {
-    return this.client.identify(context);
-  }
+  override bigSegmentStoreStatusProvider:
+  InstanceType<typeof BigSegmentStoreStatusProviderNode>;
 
-  flush(callback?: (err: Error, res: boolean) => void): Promise<void> {
-    return this.client.flush(callback);
+  constructor(options: LDOptions) {
+    super(new NodePlatform(options));
+    this.bigSegmentStoreStatusProvider = new BigSegmentStoreStatusProviderNode();
   }
 }
+
+export default Emits(LDClientNode);
diff --git a/platform-node/src/api/LDClient.ts b/platform-node/src/api/LDClient.ts
index e36c8d94c7..8e2488dc68 100644
--- a/platform-node/src/api/LDClient.ts
+++ b/platform-node/src/api/LDClient.ts
@@ -1,6 +1,6 @@
 import { LDClient as LDClientCommon } from '@launchdarkly/js-server-sdk-common';
-import EventEmitter from 'events';
-import { BigSegmentStoreStatusProvider } from './interfaces/BigSegmentStoreStatusProvider';
+import { BigSegmentStoreStatusProvider } from './interfaces';
+
 
 /**
  * The LaunchDarkly SDK client object.
@@ -10,7 +10,7 @@ import { BigSegmentStoreStatusProvider } from './interfaces/BigSegmentStoreStatu
  * the fly.
  *
  */
-export interface LDClient extends LDClientCommon, EventEmitter {
+export interface LDClient extends LDClientCommon {
   /**
    * A mechanism for tracking the status of a Big Segment store.
    *
diff --git a/platform-node/src/api/interfaces/BigSegmentStoreStatusProvider.ts b/platform-node/src/api/interfaces/BigSegmentStatusProvider.ts
similarity index 95%
rename from platform-node/src/api/interfaces/BigSegmentStoreStatusProvider.ts
rename to platform-node/src/api/interfaces/BigSegmentStatusProvider.ts
index 0ae8846d8a..13678396a4 100644
--- a/platform-node/src/api/interfaces/BigSegmentStoreStatusProvider.ts
+++ b/platform-node/src/api/interfaces/BigSegmentStatusProvider.ts
@@ -20,7 +20,7 @@ import { interfaces } from '@launchdarkly/js-server-sdk-common';
  * type of the status change event is `"change"`, and its value is the same value that would be
  * returned by {@link getStatus}.
  */
-export interface BigSegmentStoreStatusProvider extends EventEmitter {
+export interface BigSegmentStoreStatusProvider {
   /**
    * Gets the current status of the store, if known.
    *
diff --git a/platform-node/src/api/interfaces/index.ts b/platform-node/src/api/interfaces/index.ts
index 153474b58c..1ad24aaa45 100644
--- a/platform-node/src/api/interfaces/index.ts
+++ b/platform-node/src/api/interfaces/index.ts
@@ -1 +1 @@
-export * from './BigSegmentStoreStatusProvider';
+export * from '@launchdarkly/js-server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider';
diff --git a/platform-node/src/index.ts b/platform-node/src/index.ts
index c1fecbeeab..a51e695836 100644
--- a/platform-node/src/index.ts
+++ b/platform-node/src/index.ts
@@ -1,9 +1,10 @@
 import LDClientImpl from './LDClientNode';
+import BigSegmentStoreStatusProviderNode from './BigSegmentsStoreStatusProviderNode';
 
 export * from '@launchdarkly/js-server-sdk-common';
 
 // To replace the exports from `export *` we need to name them.
 // So the below exports replace them with the Node specific variants.
 
-export { LDClient, BigSegmentStoreStatusProvider } from './api';
-export { LDClientImpl };
+export { LDClient } from './api';
+export { LDClientImpl, BigSegmentStoreStatusProviderNode };
diff --git a/server-sdk-common/src/BigSegmentStatusProvider.ts b/server-sdk-common/src/BigSegmentStatusProviderImpl.ts
similarity index 78%
rename from server-sdk-common/src/BigSegmentStatusProvider.ts
rename to server-sdk-common/src/BigSegmentStatusProviderImpl.ts
index 3bf42038ae..ddc9e184d4 100644
--- a/server-sdk-common/src/BigSegmentStatusProvider.ts
+++ b/server-sdk-common/src/BigSegmentStatusProviderImpl.ts
@@ -1,9 +1,9 @@
 /* eslint-disable class-methods-use-this */
-import { BigSegmentStoreStatus } from './api/interfaces';
+import { BigSegmentStoreStatusProvider, BigSegmentStoreStatus } from './api/interfaces';
 
 type StatusHandler = (status: BigSegmentStoreStatus) => void;
 
-export default class BigSegmentStoreStatusProvider {
+export default class BigSegmentStoreStatusProviderImpl implements BigSegmentStoreStatusProvider {
   private onStatus?: StatusHandler;
 
   /**
@@ -30,7 +30,7 @@ export default class BigSegmentStoreStatusProvider {
    * handler.
    * @param handler
    */
-  setStatusHandler(handler: StatusHandler) {
+  protected setStatusHandler(handler: StatusHandler) {
     this.onStatus = handler;
   }
 }
diff --git a/server-sdk-common/src/LDClientImpl.ts b/server-sdk-common/src/LDClientImpl.ts
index 27d1b92050..99a6f0dcb1 100644
--- a/server-sdk-common/src/LDClientImpl.ts
+++ b/server-sdk-common/src/LDClientImpl.ts
@@ -3,7 +3,7 @@
 import {
   LDClient, LDContext, LDEvaluationDetail, LDFlagsState, LDFlagsStateOptions,
 } from './api';
-import BigSegmentStoreStatusProvider from './BigSegmentStatusProvider';
+import BigSegmentStoreStatusProvider from './BigSegmentStatusProviderImpl';
 import { Platform } from './platform';
 
 enum EventTypes {
@@ -39,7 +39,7 @@ export default class LDClientImpl implements LDClient {
    * a platform event system. For node this would be an EventEmitter, for other
    * platforms it would likely be an EventTarget.
    */
-  public bigSegmentStoreStatusProvider = new BigSegmentStoreStatusProvider();
+  bigSegmentStoreStatusProvider = new BigSegmentStoreStatusProvider();
 
   constructor(targetPlatform: Platform) {
     this.platform = targetPlatform;
diff --git a/server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider.ts b/server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider.ts
new file mode 100644
index 0000000000..e181ecfc47
--- /dev/null
+++ b/server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider.ts
@@ -0,0 +1,30 @@
+import { BigSegmentStoreStatus } from './BigSegmentStoreStatus';
+
+/**
+ * An interface for querying the status of a Big Segment store.
+ *
+ * The Big Segment store is the component that receives information about Big Segments, normally
+ * from a database populated by the LaunchDarkly Relay Proxy. Big Segments are a specific type of
+ * user segments. For more information, read the LaunchDarkly documentation:
+ * https://docs.launchdarkly.com/home/users/big-segments
+ *
+ * An implementation of this interface is returned by
+ * {@link LDClient.bigSegmentStoreStatusProvider}. Application code never needs to implement this
+ * interface.
+ */
+export interface BigSegmentStoreStatusProvider {
+  /**
+   * Gets the current status of the store, if known.
+   *
+   * @returns a {@link BigSegmentStoreStatus}, or `undefined` if the SDK has not yet queried the
+   *   Big Segment store status
+   */
+  getStatus(): BigSegmentStoreStatus | undefined;
+
+  /**
+   * Gets the current status of the store, querying it if the status has not already been queried.
+   *
+   * @returns a Promise for the status of the store
+   */
+  requireStatus(): Promise<BigSegmentStoreStatus>;
+}
diff --git a/server-sdk-common/src/api/interfaces/index.ts b/server-sdk-common/src/api/interfaces/index.ts
index 1a4a141cde..73c35c13b5 100644
--- a/server-sdk-common/src/api/interfaces/index.ts
+++ b/server-sdk-common/src/api/interfaces/index.ts
@@ -10,3 +10,4 @@ export * from './PersistentDataStore';
 export * from './PersistentDataStoreBase';
 export * from './PersistentDataStoreNonAtomic';
 export * from './VersionedData';
+export * from './BigSegmentStoreStatusProvider';
diff --git a/server-sdk-common/src/index.ts b/server-sdk-common/src/index.ts
index 2a3603259f..432a9d7a4c 100644
--- a/server-sdk-common/src/index.ts
+++ b/server-sdk-common/src/index.ts
@@ -1,6 +1,8 @@
 import LDClientImpl from './LDClientImpl';
+import BigSegmentStoreStatusProviderImpl from './BigSegmentStatusProviderImpl';
 
 export * as platform from './platform';
 export * from './api';
 
 export { LDClientImpl };
+export { BigSegmentStoreStatusProviderImpl };

From 5302683ee1c73a584c3455bf3aaa96d584cf8bbe Mon Sep 17 00:00:00 2001
From: Ryan Lamb <4955475+kinyoklion@users.noreply.github.com>
Date: Mon, 23 May 2022 10:24:11 -0700
Subject: [PATCH 5/7] Add implementation for emitting events for big segment
 status.

---
 .../src/BigSegmentsStoreStatusProviderNode.ts     |  6 +++++-
 .../src/BigSegmentStatusProviderImpl.ts           | 15 +++++----------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/platform-node/src/BigSegmentsStoreStatusProviderNode.ts b/platform-node/src/BigSegmentsStoreStatusProviderNode.ts
index 24ccdc61fa..ebd4e1005c 100644
--- a/platform-node/src/BigSegmentsStoreStatusProviderNode.ts
+++ b/platform-node/src/BigSegmentsStoreStatusProviderNode.ts
@@ -1,9 +1,13 @@
-import { BigSegmentStoreStatusProviderImpl } from '@launchdarkly/js-server-sdk-common';
+import { BigSegmentStoreStatusProviderImpl, interfaces } from '@launchdarkly/js-server-sdk-common';
 import EventEmitter from 'events';
 import { Emits } from './Emits';
 
 class BigSegmentStoreStatusProviderNode extends BigSegmentStoreStatusProviderImpl {
   emitter: EventEmitter = new EventEmitter();
+
+  override dispatch(eventType: string, status: interfaces.BigSegmentStoreStatus) {
+    this.emitter.emit(eventType, status);
+  }
 }
 
 export default Emits(BigSegmentStoreStatusProviderNode);
diff --git a/server-sdk-common/src/BigSegmentStatusProviderImpl.ts b/server-sdk-common/src/BigSegmentStatusProviderImpl.ts
index ddc9e184d4..fa457409e8 100644
--- a/server-sdk-common/src/BigSegmentStatusProviderImpl.ts
+++ b/server-sdk-common/src/BigSegmentStatusProviderImpl.ts
@@ -1,11 +1,7 @@
 /* eslint-disable class-methods-use-this */
 import { BigSegmentStoreStatusProvider, BigSegmentStoreStatus } from './api/interfaces';
 
-type StatusHandler = (status: BigSegmentStoreStatus) => void;
-
 export default class BigSegmentStoreStatusProviderImpl implements BigSegmentStoreStatusProvider {
-  private onStatus?: StatusHandler;
-
   /**
    * Gets the current status of the store, if known.
    *
@@ -26,11 +22,10 @@ export default class BigSegmentStoreStatusProviderImpl implements BigSegmentStor
   }
 
   /**
-   * Set the status handler. Only one handler can be registered and this will replace the existing
-   * handler.
-   * @param handler
+   * This should be overridden by derived implementations.
+   * @param eventType
+   * @param status
    */
-  protected setStatusHandler(handler: StatusHandler) {
-    this.onStatus = handler;
-  }
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  dispatch(eventType: string, status: BigSegmentStoreStatus) {}
 }

From 263fccdefcd92326224d5274d8cb84c8936369b0 Mon Sep 17 00:00:00 2001
From: Ryan Lamb <4955475+kinyoklion@users.noreply.github.com>
Date: Mon, 23 May 2022 10:25:45 -0700
Subject: [PATCH 6/7] Add documentation.

---
 platform-node/src/Emits.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/platform-node/src/Emits.ts b/platform-node/src/Emits.ts
index 57addc03f9..7cbbf919f6 100644
--- a/platform-node/src/Emits.ts
+++ b/platform-node/src/Emits.ts
@@ -3,6 +3,12 @@ import EventEmitter from 'events';
 export type EventableConstructor<T = {}> = new (...args: any[]) => T;
 export type Eventable = EventableConstructor<{ emitter: EventEmitter }>;
 
+/**
+ * Adds the implementation of an event emitter to something that contains
+ * a field of `emitter` with type `EventEmitter`.
+ * @param Base The class to derive the mixin from.
+ * @returns A class extending the base with an event emitter.
+ */
 export function Emits<TBase extends Eventable>(Base: TBase) {
   return class WithEvents extends Base {
     addListener(eventName: string | symbol, listener: (...args: any[]) => void): this {
@@ -71,4 +77,4 @@ export function Emits<TBase extends Eventable>(Base: TBase) {
       return this.emitter.eventNames();
     }
   };
-}
\ No newline at end of file
+}

From 831b964933bddfa9da2fb3c8ff81a551ff1706a7 Mon Sep 17 00:00:00 2001
From: Ryan Lamb <4955475+kinyoklion@users.noreply.github.com>
Date: Mon, 23 May 2022 10:34:32 -0700
Subject: [PATCH 7/7] Fix lint and interface hierarchy.

---
 platform-node/src/LDClientNode.ts                            | 3 ---
 platform-node/src/api/LDClient.ts                            | 4 ++--
 platform-node/src/api/interfaces/BigSegmentStatusProvider.ts | 2 +-
 platform-node/src/api/interfaces/index.ts                    | 2 +-
 4 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/platform-node/src/LDClientNode.ts b/platform-node/src/LDClientNode.ts
index 6204e6cfb0..8079063093 100644
--- a/platform-node/src/LDClientNode.ts
+++ b/platform-node/src/LDClientNode.ts
@@ -1,6 +1,3 @@
-/* eslint-disable @typescript-eslint/no-unused-vars */
-/* eslint-disable class-methods-use-this */
-// eslint-disable-next-line max-classes-per-file
 import {
   LDClientImpl, LDOptions,
 } from '@launchdarkly/js-server-sdk-common';
diff --git a/platform-node/src/api/LDClient.ts b/platform-node/src/api/LDClient.ts
index 8e2488dc68..5c7f331556 100644
--- a/platform-node/src/api/LDClient.ts
+++ b/platform-node/src/api/LDClient.ts
@@ -1,7 +1,7 @@
 import { LDClient as LDClientCommon } from '@launchdarkly/js-server-sdk-common';
+import EventEmitter from 'events';
 import { BigSegmentStoreStatusProvider } from './interfaces';
 
-
 /**
  * The LaunchDarkly SDK client object.
  *
@@ -10,7 +10,7 @@ import { BigSegmentStoreStatusProvider } from './interfaces';
  * the fly.
  *
  */
-export interface LDClient extends LDClientCommon {
+export interface LDClient extends LDClientCommon, EventEmitter {
   /**
    * A mechanism for tracking the status of a Big Segment store.
    *
diff --git a/platform-node/src/api/interfaces/BigSegmentStatusProvider.ts b/platform-node/src/api/interfaces/BigSegmentStatusProvider.ts
index 13678396a4..0ae8846d8a 100644
--- a/platform-node/src/api/interfaces/BigSegmentStatusProvider.ts
+++ b/platform-node/src/api/interfaces/BigSegmentStatusProvider.ts
@@ -20,7 +20,7 @@ import { interfaces } from '@launchdarkly/js-server-sdk-common';
  * type of the status change event is `"change"`, and its value is the same value that would be
  * returned by {@link getStatus}.
  */
-export interface BigSegmentStoreStatusProvider {
+export interface BigSegmentStoreStatusProvider extends EventEmitter {
   /**
    * Gets the current status of the store, if known.
    *
diff --git a/platform-node/src/api/interfaces/index.ts b/platform-node/src/api/interfaces/index.ts
index 1ad24aaa45..19659eab65 100644
--- a/platform-node/src/api/interfaces/index.ts
+++ b/platform-node/src/api/interfaces/index.ts
@@ -1 +1 @@
-export * from '@launchdarkly/js-server-sdk-common/src/api/interfaces/BigSegmentStoreStatusProvider';
+export * from './BigSegmentStatusProvider';