Refactor the client lifecycle methods (destroy, init, flush) for reusability

src/sdkClient/sdkClient.ts

@@ -1,40 +1,16 @@
 import { objectAssign } from '../utils/lang/objectAssign';
 import SplitIO from '../../types/splitio';
-import { releaseApiKey, validateAndTrackApiKey } from '../utils/inputValidation/apiKey';
 import { clientFactory } from './client';
 import { clientInputValidationDecorator } from './clientInputValidation';
 import { ISdkFactoryContext } from '../sdkFactory/types';
-
-const COOLDOWN_TIME_IN_MILLIS = 1000;
+import { sdkLifecycleFactory } from './sdkLifecycle';
 
 /**
  * Creates an Sdk client, i.e., a base client with status, init, flush and destroy interface
  */
 export function sdkClientFactory(params: ISdkFactoryContext, isSharedClient?: boolean): SplitIO.IClient | SplitIO.IAsyncClient {
-  const { sdkReadinessManager, syncManager, storage, signalListener, settings, telemetryTracker, impressionsTracker } = params;
-
-  let hasInit = false;
-  let lastActionTime = 0;
-
-  function __cooldown(func: Function, time: number) {
-    const now = Date.now();
-    //get the actual time elapsed in ms
-    const timeElapsed = now - lastActionTime;
-    //check if the time elapsed is less than desired cooldown
-    if (timeElapsed < time) {
-      //if yes, return message with remaining time in seconds
-      settings.log.warn(`Flush cooldown, remaining time ${(time - timeElapsed) / 1000} seconds`);
-      return Promise.resolve();
-    } else {
-      //Do the requested action and re-assign the lastActionTime
-      lastActionTime = now;
-      return func();
-    }
-  }
+  const { sdkReadinessManager, settings } = params;
 
-  function __flush() {
-    return syncManager ? syncManager.flush() : Promise.resolve();
-  }
 
   return objectAssign(
     // Proto-linkage of the readiness Event Emitter
@@ -48,46 +24,6 @@ export function sdkClientFactory(params: ISdkFactoryContext, isSharedClient?: bo
       params.fallbackCalculator
     ),
 
-    {
-      init() {
-        if (hasInit) return;
-        hasInit = true;
-
-        if (!isSharedClient) {
-          validateAndTrackApiKey(settings.log, settings.core.authorizationKey);
-          sdkReadinessManager.readinessManager.init();
-          impressionsTracker.start();
-          syncManager && syncManager.start();
-          signalListener && signalListener.start();
-        }
-      },
-
-      flush() {
-        // @TODO define cooldown time
-        return __cooldown(__flush, COOLDOWN_TIME_IN_MILLIS);
-      },
-
-      destroy() {
-        hasInit = false;
-        // Mark the SDK as destroyed immediately
-        sdkReadinessManager.readinessManager.destroy();
-
-        // For main client, cleanup the SDK Key, listeners and scheduled jobs, and record stat before flushing data
-        if (!isSharedClient) {
-          releaseApiKey(settings.core.authorizationKey);
-          telemetryTracker.sessionLength();
-          signalListener && signalListener.stop();
-          impressionsTracker.stop();
-        }
-
-        // Stop background jobs
-        syncManager && syncManager.stop();
-
-        return __flush().then(() => {
-          // Cleanup storage
-          return storage.destroy();
-        });
-      }
-    }
+    sdkLifecycleFactory(params, isSharedClient)
   );
 }

src/sdkClient/sdkLifecycle.ts

@@ -0,0 +1,76 @@
+import { releaseApiKey, validateAndTrackApiKey } from '../utils/inputValidation/apiKey';
+import { ISdkFactoryContext } from '../sdkFactory/types';
+
+const COOLDOWN_TIME_IN_MILLIS = 1000;
+
+/**
+ * Creates an Sdk client, i.e., a base client with status, init, flush and destroy interface
+ */
+export function sdkLifecycleFactory(params: ISdkFactoryContext, isSharedClient?: boolean): { init(): void; flush(): Promise<void>; destroy(): Promise<void> } {
+  const { sdkReadinessManager, syncManager, storage, signalListener, settings, telemetryTracker, impressionsTracker } = params;
+
+  let hasInit = false;
+  let lastActionTime = 0;
+
+  function __cooldown(func: Function, time: number) {
+    const now = Date.now();
+    //get the actual time elapsed in ms
+    const timeElapsed = now - lastActionTime;
+    //check if the time elapsed is less than desired cooldown
+    if (timeElapsed < time) {
+      //if yes, return message with remaining time in seconds
+      settings.log.warn(`Flush cooldown, remaining time ${(time - timeElapsed) / 1000} seconds`);
+      return Promise.resolve();
+    } else {
+      //Do the requested action and re-assign the lastActionTime
+      lastActionTime = now;
+      return func();
+    }
+  }
+
+  function __flush() {
+    return syncManager ? syncManager.flush() : Promise.resolve();
+  }
+
+  return {
+    init() {
+      if (hasInit) return;
+      hasInit = true;
+
+      if (!isSharedClient) {
+        validateAndTrackApiKey(settings.log, settings.core.authorizationKey);
+        sdkReadinessManager.readinessManager.init();
+        impressionsTracker.start();
+        syncManager && syncManager.start();
+        signalListener && signalListener.start();
+      }
+    },
+
+    flush() {
+      // @TODO define cooldown time
+      return __cooldown(__flush, COOLDOWN_TIME_IN_MILLIS);
+    },
+
+    destroy() {
+      hasInit = false;
+      // Mark the SDK as destroyed immediately
+      sdkReadinessManager.readinessManager.destroy();
+
+      // For main client, cleanup the SDK Key, listeners and scheduled jobs, and record stat before flushing data
+      if (!isSharedClient) {
+        releaseApiKey(settings.core.authorizationKey);
+        telemetryTracker.sessionLength();
+        signalListener && signalListener.stop();
+        impressionsTracker.stop();
+      }
+
+      // Stop background jobs
+      syncManager && syncManager.stop();
+
+      return __flush().then(() => {
+        // Cleanup storage
+        return storage.destroy();
+      });
+    }
+  };
+}