[core/api] store single instance of UserFlags

packages/core/src/api/app/FeatureFlags.test.tsx

@@ -43,6 +43,7 @@ describe('FeatureFlags', () => {
         }),
       );
 
+      featureFlags = new FeatureFlagsImpl();
       expect(featureFlags.getFlags().toObject()).toMatchObject({
         'feature-flag-one': FeatureFlagState.Enabled,
         'feature-flag-two': FeatureFlagState.Enabled,
@@ -59,6 +60,8 @@ describe('FeatureFlags', () => {
         }),
       );
 
+      featureFlags = new FeatureFlagsImpl();
+
       expect(featureFlags.getFlags().get('feature-flag-one')).toEqual(
         FeatureFlagState.Enabled,
       );
@@ -89,6 +92,7 @@ describe('FeatureFlags', () => {
         }),
       );
 
+      featureFlags = new FeatureFlagsImpl();
       const flags = featureFlags.getFlags();
       flags.delete('feature-flag-one');
 

packages/core/src/api/app/FeatureFlags.tsx

@@ -168,9 +168,10 @@ export class FeatureFlagsRegistry extends Array<FeatureFlagsRegistryItem> {
  */
 export class FeatureFlags implements FeatureFlagsApi {
   public registeredFeatureFlags: FeatureFlagsRegistryItem[] = [];
+  private readonly userFlags: UserFlags = new UserFlags();
 
   getFlags(): UserFlags {
-    return new UserFlags();
+    return this.userFlags;
   }
 
   getRegisteredFlags(): FeatureFlagsRegistry {