[FSSDK-11528] Holdout support in decision service (#1075)

junaed-optimizely · raju-opti · commit 7b5dc4395239 · 2025-09-02T20:23:00.000+06:00
diff --git a/lib/feature_toggle.ts b/lib/feature_toggle.ts
@@ -31,4 +31,6 @@
  * flag and all associated checks can be removed from the codebase.
  */
 
-export const holdout = () => true;
+export const holdout = () => false as const;
+
+export type IfActive<T extends () => boolean, Y, N = unknown> = ReturnType<T> extends true ? Y : N;
diff --git a/lib/notification_center/type.ts b/lib/notification_center/type.ts
@@ -26,14 +26,16 @@ import {
 } from '../shared_types';
 import { DecisionSource } from '../utils/enums';
 import { Nullable } from '../utils/type';
+import { holdout, IfActive } from '../feature_toggle';
 
 export type UserEventListenerPayload = {
   userId: string;
   attributes?: UserAttributes;
 }
 
 export type ActivateListenerPayload = UserEventListenerPayload & {
-  experiment: Experiment | Holdout | null;
+  experiment: Experiment | null;
+  holdout: IfActive<typeof holdout, Holdout | null>;
   variation: Variation | null;
   logEvent: LogEvent;
 }
diff --git a/lib/optimizely/index.spec.ts b/lib/optimizely/index.spec.ts
@@ -249,7 +249,8 @@ describe('Optimizely', () => {
     let projectConfig: any;
     let optimizely: any;
     let decisionService: any;
-    let notificationSpy: any;
+    let flagNotificationSpy: any;
+    let activateNotificationSpy: any;
     let eventProcessor: any;
 
     beforeEach(() => {
@@ -282,10 +283,16 @@ describe('Optimizely', () => {
       decisionService = optimizely.decisionService;
 
       // Setup notification spy
-      notificationSpy = vi.fn();
+      flagNotificationSpy = vi.fn();
       optimizely.notificationCenter.addNotificationListener(
         NOTIFICATION_TYPES.DECISION,
-        notificationSpy
+        flagNotificationSpy
+      );
+
+      activateNotificationSpy = vi.fn();
+      optimizely.notificationCenter.addNotificationListener(
+        NOTIFICATION_TYPES.ACTIVATE,
+        activateNotificationSpy
       );
     });
 
@@ -408,7 +415,7 @@ describe('Optimizely', () => {
       expect(decision.ruleKey).toBe('holdout_test_key');
 
       // Verify decision notification was sent
-      expect(notificationSpy).toHaveBeenCalledWith({
+      expect(flagNotificationSpy).toHaveBeenCalledWith({
         type: DECISION_NOTIFICATION_TYPES.FLAG,
         userId: 'test_user',
         attributes: { country: 'US' },
@@ -422,6 +429,14 @@ describe('Optimizely', () => {
           decisionEventDispatched: true,
         }),
       });
+
+      expect(activateNotificationSpy).toHaveBeenCalledWith(expect.objectContaining({
+        experiment: null,
+        holdout: projectConfig.holdouts[0],
+        userId: 'test_user',
+        attributes: { country: 'US' },
+        variation: projectConfig.holdouts[0].variations[0]
+      }));
     });
 
     it('should handle holdout with included flags', async () => {
@@ -455,7 +470,7 @@ describe('Optimizely', () => {
       expect(decision.variationKey).toBe('holdout_variation_key');
 
       // Verify notification shows holdout details
-      expect(notificationSpy).toHaveBeenCalledWith({
+      expect(flagNotificationSpy).toHaveBeenCalledWith({
         type: DECISION_NOTIFICATION_TYPES.FLAG,
         userId: 'test_user',
         attributes: { country: 'US' },
@@ -465,6 +480,14 @@ describe('Optimizely', () => {
           ruleKey: 'holdout_test_key',
         }),
       });
+
+      expect(activateNotificationSpy).toHaveBeenCalledWith(expect.objectContaining({
+        experiment: null,
+        holdout: modifiedHoldout,
+        userId: 'test_user',
+        attributes: { country: 'US' },
+        variation: modifiedHoldout.variations[0]
+      }));
     });
 
     it('should handle holdout with excluded flags', async () => {
@@ -499,7 +522,7 @@ describe('Optimizely', () => {
       expect(decision.variationKey).toBe('variation_3');
 
       // Verify notification shows normal experiment details (not holdout)
-      expect(notificationSpy).toHaveBeenCalledWith({
+      expect(flagNotificationSpy).toHaveBeenCalledWith({
         type: DECISION_NOTIFICATION_TYPES.FLAG,
         userId: 'test_user',
         attributes: { country: 'BD', age: 80 },
@@ -509,6 +532,14 @@ describe('Optimizely', () => {
           ruleKey: 'exp_3',
         }),
       });
+
+      expect(activateNotificationSpy).toHaveBeenCalledWith(expect.objectContaining({
+        experiment: projectConfig.experimentKeyMap['exp_3'],
+        holdout: null,
+        userId: 'test_user',
+        attributes: { country: 'BD', age: 80 },
+        variation: projectConfig.variationIdMap['5003']
+      }));
     });
 
     it('should handle multiple holdouts with correct priority', async () => {
@@ -568,7 +599,7 @@ describe('Optimizely', () => {
       expect(decision.variationKey).toBe('holdout_variation_key_2');
 
       // Verify notification shows details of selected holdout
-      expect(notificationSpy).toHaveBeenCalledWith({
+      expect(flagNotificationSpy).toHaveBeenCalledWith({
         type: DECISION_NOTIFICATION_TYPES.FLAG,
         userId: 'test_user',
         attributes: { country: 'US' },
@@ -578,6 +609,14 @@ describe('Optimizely', () => {
           ruleKey: 'holdout_test_key_2',
         }),
       });
+
+      expect(activateNotificationSpy).toHaveBeenCalledWith(expect.objectContaining({
+        experiment: null,
+        holdout: holdout2,
+        userId: 'test_user',
+        attributes: { country: 'US' },
+        variation: holdout2.variations[0]
+      }));
     });
 
     it('should respect sendFlagDecisions setting for holdout events - false', async () => {
@@ -744,7 +783,7 @@ describe('Optimizely', () => {
       expect(typeof decision.variables).toBe('object');
 
       // Verify notification includes variable information
-      expect(notificationSpy).toHaveBeenCalledWith({
+      expect(flagNotificationSpy).toHaveBeenCalledWith({
         type: DECISION_NOTIFICATION_TYPES.FLAG,
         userId: 'test_user',
         attributes: { country: 'US' },
@@ -754,6 +793,14 @@ describe('Optimizely', () => {
           enabled: false,
         }),
       });
+
+      expect(activateNotificationSpy).toHaveBeenCalledWith(expect.objectContaining({
+        experiment: null,
+        holdout: projectConfig.holdouts[0],
+        userId: 'test_user',
+        attributes: { country: 'US' },
+        variation: projectConfig.holdouts[0].variations[0]
+      }));
     });
 
     it('should handle disable decision event option for holdout', async () => {
diff --git a/lib/optimizely/index.tests.js b/lib/optimizely/index.tests.js
@@ -67,6 +67,7 @@ import {
 
 import { USER_BUCKETED_INTO_EXPERIMENT_IN_GROUP } from '../core/bucketer';
 import { resolvablePromise } from '../utils/promise/resolvablePromise';
+import { holdout } from '../feature_toggle';
 
 var LOG_LEVEL = enums.LOG_LEVEL;
 var DECISION_SOURCES = enums.DECISION_SOURCES;
@@ -2281,6 +2282,7 @@ describe('lib/optimizely', function() {
         var instanceExperiments = optlyInstance.projectConfigManager.getConfig().experiments;
         var expectedArgument = {
           experiment: instanceExperiments[0],
+          holdout: null,
           userId: 'testUser',
           attributes: undefined,
           variation: instanceExperiments[0].variations[1],
@@ -2351,6 +2353,7 @@ describe('lib/optimizely', function() {
         var instanceExperiments = optlyInstance.projectConfigManager.getConfig().experiments;
         var expectedArgument = {
           experiment: instanceExperiments[0],
+          holdout: null,
           userId: 'testUser',
           attributes: attributes,
           variation: instanceExperiments[0].variations[1],
diff --git a/lib/optimizely/index.ts b/lib/optimizely/index.ts
@@ -37,6 +37,7 @@ import {
   OptimizelyDecision,
   Client,
   UserProfileServiceAsync,
+  isHoldout,
 } from '../shared_types';
 import { newErrorDecision } from '../optimizely_decision';
 import OptimizelyUserContext from '../optimizely_user_context';
@@ -62,7 +63,7 @@ import {
 import { Fn, Maybe, OpType } from '../utils/type';
 import { resolvablePromise } from '../utils/promise/resolvablePromise';
 
-import { NOTIFICATION_TYPES, DecisionNotificationType, DECISION_NOTIFICATION_TYPES } from '../notification_center/type';
+import { NOTIFICATION_TYPES, DecisionNotificationType, DECISION_NOTIFICATION_TYPES, ActivateListenerPayload } from '../notification_center/type';
 import {
   FEATURE_NOT_IN_DATAFILE,
   INVALID_INPUT_FORMAT,
@@ -382,17 +383,29 @@ export default class Optimizely extends BaseService implements Client {
     this.eventProcessor.process(impressionEvent);
 
     const logEvent = buildLogEvent([impressionEvent]);
-    this.notificationCenter.sendNotifications(NOTIFICATION_TYPES.ACTIVATE, {
-      experiment: decisionObj.experiment,
+
+    const activateNotificationPayload: ActivateListenerPayload = {
+      experiment: null,
+      holdout: null,
       userId: userId,
       attributes: attributes,
       variation: decisionObj.variation,
       logEvent,
-    });
+    };
+
+    if (decisionObj.experiment) {
+      if (isHoldout(decisionObj.experiment)) {
+        activateNotificationPayload.holdout = decisionObj.experiment;
+      } else {
+        activateNotificationPayload.experiment = decisionObj.experiment;
+      }
+    }
+
+    this.notificationCenter.sendNotifications(NOTIFICATION_TYPES.ACTIVATE, activateNotificationPayload);
   }
 
   /**
-   * Sends conversion event to Optimizely.
+   * Sends conversion event to Optimizely.`
    * @param  {string}         eventKey
    * @param  {string}         userId
    * @param  {UserAttributes} attributes
diff --git a/lib/shared_types.ts b/lib/shared_types.ts
@@ -181,6 +181,15 @@ export interface Holdout extends ExperimentCore {
   excludedFlags: string[];
 }
 
+export function isHoldout(obj: Experiment | Holdout): obj is Holdout {
+  // Holdout has 'status', 'includedFlags', and 'excludedFlags' properties
+  return (
+    (obj as Holdout).status !== undefined &&
+    Array.isArray((obj as Holdout).includeFlags) &&
+    Array.isArray((obj as Holdout).excludeFlags)
+  );
+}
+
 export enum VariableType {
   BOOLEAN = 'boolean',
   DOUBLE = 'double',
