feat!: add events to in-memory provider (#436)

Signed-off-by: Lukas Reining <lukas.reining@codecentric.de> Co-authored-by: Todd Baert <todd.baert@dynatrace.com>
open-feature · Jul 6, 2023 · 626cda8 · 626cda8
1 parent d2a3109
commit 626cda8
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Showing 3 changed files with 48 additions and 7 deletions.
diff --git a/libs/providers/in-memory/package.json b/libs/providers/in-memory/package.json
@@ -7,6 +7,6 @@
     "current-version": "echo $npm_package_version"
   },
   "peerDependencies": {
-    "@openfeature/js-sdk": "^1.0.0"
+    "@openfeature/js-sdk": "^1.3.0"
   }
 }
diff --git a/libs/providers/in-memory/src/lib/in-memory-provider.spec.ts b/libs/providers/in-memory/src/lib/in-memory-provider.spec.ts
@@ -1,6 +1,7 @@
 import {
   FlagNotFoundError,
   GeneralError,
+  ProviderEvents,
   ResolutionDetails,
   StandardResolutionReasons,
   TypeMismatchError,
@@ -112,11 +113,44 @@ describe(InMemoryProvider, () => {
     const resolution = await provider.resolveStringEvaluation('some-flag');
     verifyResolution(resolution, { expectedValue: 'initial-value' });
   });
+
+  describe('events', () => {
+    it('emits provider changed event if a new value is added', (done) => {
+      const configuration = {
+        'some-flag': 'initial-value',
+      };
+      const provider = new InMemoryProvider(configuration);
+
+      provider.events.addHandler(ProviderEvents.ConfigurationChanged, (details) => {
+        expect(details?.flagsChanged).toEqual(['some-other-flag']);
+        done();
+      });
+
+      const newConfiguration = { ...configuration, 'some-other-flag': 'value' };
+      provider.replaceConfiguration(newConfiguration);
+    });
+
+    it('emits provider changed event if an existing value is changed', (done) => {
+      const configuration = {
+        'some-flag': 'initial-value',
+      };
+      const provider = new InMemoryProvider(configuration);
+
+      provider.events.addHandler(ProviderEvents.ConfigurationChanged, (details) => {
+        expect(details?.flagsChanged).toEqual(['some-flag']);
+        done();
+      });
+
+      const newConfiguration = { 'some-flag': 'new-value' };
+      provider.replaceConfiguration(newConfiguration);
+    });
+  });
 });
 
 type VerifyResolutionParams<U> = {
   expectedValue: U;
 };
+
 function verifyResolution<U>(resolution: ResolutionDetails<U>, { expectedValue }: VerifyResolutionParams<U>) {
   expect(resolution.value).toBe(expectedValue);
   expect(resolution.reason).toBe(StandardResolutionReasons.STATIC);

diff --git a/libs/providers/in-memory/src/lib/in-memory-provider.ts b/libs/providers/in-memory/src/lib/in-memory-provider.ts
@@ -1,17 +1,19 @@
 import {
-  EvaluationContext,
-  Provider,
+  FlagNotFoundError,
+  FlagValue,
+  GeneralError,
   JsonValue,
+  OpenFeatureEventEmitter,
+  Provider,
+  ProviderEvents,
   ResolutionDetails,
-  FlagNotFoundError,
-  TypeMismatchError,
   StandardResolutionReasons,
-  GeneralError,
-  FlagValue,
+  TypeMismatchError,
 } from '@openfeature/js-sdk';
 import { FlagConfiguration } from './flag-configuration';
 
 export class InMemoryProvider implements Provider {
+  public readonly events = new OpenFeatureEventEmitter();
   readonly metadata = {
     name: 'In-Memory Provider',
   } as const;
@@ -22,7 +24,12 @@ export class InMemoryProvider implements Provider {
   }
 
   replaceConfiguration(flagConfiguration: FlagConfiguration) {
+    const flagsChanged = Object.entries(flagConfiguration)
+      .filter(([key, value]) => this._flagConfiguration[key] !== value)
+      .map(([key]) => key);
+
     this._flagConfiguration = { ...flagConfiguration };
+    this.events.emit(ProviderEvents.ConfigurationChanged, { flagsChanged });
   }
 
   async resolveBooleanEvaluation(flagKey: string): Promise<ResolutionDetails<boolean>> {