feat: add InMemoryHandler for offline handlers without a filesystem

index.ts

@@ -11,7 +11,7 @@ export {
     Flagsmith
 } from './sdk/index.js';
 
-export { BaseOfflineHandler, LocalFileHandler } from './sdk/offline_handlers.js';
+export { BaseOfflineHandler, InMemoryHandler, LocalFileHandler } from './sdk/offline_handlers.js';
 
 export { FlagsmithConfig, FlagsmithValue, TraitConfig } from './sdk/types.js';
 

sdk/offline_handlers.ts

@@ -8,15 +8,24 @@ export class BaseOfflineHandler {
     }
 }
 
-export class LocalFileHandler extends BaseOfflineHandler {
+/**
+ * Handler for an environment document already in memory, as returned by the
+ * `/api/v1/environment-document` endpoint and parsed.
+ */
+export class InMemoryHandler extends BaseOfflineHandler {
     environment: EnvironmentModel;
-    constructor(environment_document_path: string) {
+    constructor(environment_document: object) {
         super();
-        const environment_document = fs.readFileSync(environment_document_path, 'utf8');
-        this.environment = buildEnvironmentModel(JSON.parse(environment_document));
+        this.environment = buildEnvironmentModel(environment_document);
     }
 
     getEnvironment(): EnvironmentModel {
         return this.environment;
     }
 }
+
+export class LocalFileHandler extends InMemoryHandler {
+    constructor(environment_document_path: string) {
+        super(JSON.parse(fs.readFileSync(environment_document_path, 'utf8')));
+    }
+}

tests/sdk/offline-handlers.test.ts

@@ -1,5 +1,5 @@
 import * as fs from 'fs';
-import { LocalFileHandler } from '../../sdk/offline_handlers.js';
+import { InMemoryHandler, LocalFileHandler } from '../../sdk/offline_handlers.js';
 import { EnvironmentModel } from '../../flagsmith-engine/index.js';
 
 import * as offlineEnvironment from './data/offline-environment.json';
@@ -32,3 +32,15 @@ test.skipIf(isEsmBuild)('local file handler', () => {
     // Restore the original implementation of fs.readFileSync
     readFileSyncMock.mockRestore();
 });
+
+test.skipIf(isEsmBuild)('in memory handler', () => {
+    // Given
+    const inMemoryHandler = new InMemoryHandler(offlineEnvironment);
+
+    // When
+    const environmentModel = inMemoryHandler.getEnvironment();
+
+    // Then
+    expect(environmentModel).toBeInstanceOf(EnvironmentModel);
+    expect(environmentModel.apiKey).toBe('B62qaMZNwfiqT76p38ggrQ');
+});