External configuration

Author: kinyoklion

packages/sdk/browser/example/src/app.ts

@@ -25,7 +25,8 @@ statusBox.appendChild(document.createTextNode('Initializing...'));
 
 const main = async () => {
   const ldclient = createClient(clientSideID, context, {
-    useFDv2: true,
+    // @ts-ignore dataSystem is @internal — experimental FDv2 opt-in
+    dataSystem: {},
   });
   const render = () => {
     const flagValue = ldclient.variation(flagKey, false);

packages/sdk/browser/src/BrowserClient.ts

@@ -1,11 +1,14 @@
 import {
   AutoEnvAttributes,
   BasicLogger,
+  BROWSER_DATA_SYSTEM_DEFAULTS,
   browserFdv1Endpoints,
   Configuration,
+  dataSystemValidators,
   FlagManager,
   Hook,
   internal,
+  LDClientDataSystemOptions,
   LDClientImpl,
   LDContext,
   LDEmitter,
@@ -19,6 +22,7 @@ import {
   Platform,
   readFlagsFromBootstrap,
   safeRegisterDebugOverridePlugins,
+  validateOptions,
 } from '@launchdarkly/js-client-sdk-common';
 
 import { getHref } from './BrowserApi';
@@ -78,41 +82,53 @@ class BrowserClientImpl extends LDClientImpl {
     const { eventUrlTransformer } = validatedBrowserOptions;
     const endpoints = browserFdv1Endpoints(clientSideId);
 
-    const dataManagerFactory = validatedBrowserOptions.useFDv2
-      ? (
-          flagManager: FlagManager,
-          configuration: Configuration,
-          baseHeaders: LDHeaders,
-          emitter: LDEmitter,
-          _diagnosticsManager?: internal.DiagnosticsManager,
-        ) =>
-          new BrowserFDv2DataManager(
-            platform,
-            flagManager,
-            clientSideId,
-            configuration,
-            baseHeaders,
-            emitter,
-          )
-      : (
-          flagManager: FlagManager,
-          configuration: Configuration,
-          baseHeaders: LDHeaders,
-          emitter: LDEmitter,
-          diagnosticsManager?: internal.DiagnosticsManager,
-        ) =>
-          new BrowserDataManager(
-            platform,
-            flagManager,
-            clientSideId,
-            configuration,
-            validatedBrowserOptions,
-            endpoints.polling,
-            endpoints.streaming,
-            baseHeaders,
-            emitter,
-            diagnosticsManager,
-          );
+    const validatedDataSystem =
+      options.dataSystem !== undefined
+        ? (validateOptions(
+            options.dataSystem,
+            dataSystemValidators,
+            BROWSER_DATA_SYSTEM_DEFAULTS as unknown as Record<string, unknown>,
+            logger,
+            'dataSystem',
+          ) as unknown as LDClientDataSystemOptions)
+        : undefined;
+
+    const dataManagerFactory =
+      validatedDataSystem !== undefined
+        ? (
+            flagManager: FlagManager,
+            configuration: Configuration,
+            baseHeaders: LDHeaders,
+            emitter: LDEmitter,
+            _diagnosticsManager?: internal.DiagnosticsManager,
+          ) =>
+            new BrowserFDv2DataManager(
+              platform,
+              flagManager,
+              clientSideId,
+              configuration,
+              baseHeaders,
+              emitter,
+            )
+        : (
+            flagManager: FlagManager,
+            configuration: Configuration,
+            baseHeaders: LDHeaders,
+            emitter: LDEmitter,
+            diagnosticsManager?: internal.DiagnosticsManager,
+          ) =>
+            new BrowserDataManager(
+              platform,
+              flagManager,
+              clientSideId,
+              configuration,
+              validatedBrowserOptions,
+              endpoints.polling,
+              endpoints.streaming,
+              baseHeaders,
+              emitter,
+              diagnosticsManager,
+            );
 
     super(clientSideId, autoEnvAttributes, platform, baseOptionsWithDefaults, dataManagerFactory, {
       // This logic is derived from https://github.com/launchdarkly/js-sdk-common/blob/main/src/PersistentFlagStore.js

packages/sdk/browser/src/options.ts

@@ -59,15 +59,6 @@ export interface BrowserOptions extends Omit<LDOptionsBase, 'initialConnectionMo
    * A list of plugins to be used with the SDK.
    */
   plugins?: LDPlugin[];
-
-  /**
-   * Opt-in to the FDv2 data delivery protocol. When enabled, the SDK uses
-   * the new `/sdk/poll/eval` and `/sdk/stream/eval` endpoints with the
-   * FDv2 protocol handler and orchestrator.
-   *
-   * Default: false
-   */
-  useFDv2?: boolean;
 }
 
 export interface ValidatedOptions {
@@ -76,23 +67,20 @@ export interface ValidatedOptions {
   streaming?: boolean;
   automaticBackgroundHandling?: boolean;
   plugins: LDPlugin[];
-  useFDv2: boolean;
 }
 
 const optDefaults = {
   fetchGoals: true,
   eventUrlTransformer: (url: string) => url,
   streaming: undefined,
   plugins: [],
-  useFDv2: false,
 };
 
 const validators: { [Property in keyof BrowserOptions]: TypeValidator | undefined } = {
   fetchGoals: TypeValidators.Boolean,
   eventUrlTransformer: TypeValidators.Function,
   streaming: TypeValidators.Boolean,
   plugins: TypeValidators.createTypeArray('LDPlugin', {}),
-  useFDv2: TypeValidators.Boolean,
 };
 
 function withBrowserDefaults(opts: BrowserOptions): BrowserOptions {

packages/shared/sdk-client/src/api/LDOptions.ts

@@ -1,5 +1,6 @@
 import type { LDLogger } from '@launchdarkly/js-sdk-common';
 
+import { LDClientDataSystemOptions } from './datasource/LDClientDataSystemOptions';
 import { Hook } from './integrations/Hooks';
 import { LDInspection } from './LDInspection';
 
@@ -279,4 +280,19 @@ export interface LDOptions {
    * @defaultValue false.
    */
   cleanOldPersistentData?: boolean;
+
+  /**
+   * @internal
+   *
+   * WARNING: This option is EXPERIMENTAL and UNSUPPORTED. It is subject to
+   * change or removal without notice. Do not use in production applications.
+   * Using this option may result in unexpected behavior, data loss, or
+   * breaking changes in future SDK versions. LaunchDarkly does not provide
+   * support for configurations using this option.
+   *
+   * Configuration for the FDv2 data system. When present, the SDK uses
+   * the FDv2 protocol for flag delivery instead of the default FDv1
+   * protocol.
+   */
+  dataSystem?: LDClientDataSystemOptions;
 }

packages/shared/sdk-client/src/configuration/Configuration.ts

@@ -10,6 +10,7 @@ import {
 } from '@launchdarkly/js-sdk-common';
 
 import { Hook, type LDOptions } from '../api';
+import type { LDClientDataSystemOptions } from '../api/datasource/LDClientDataSystemOptions';
 import { LDInspection } from '../api/LDInspection';
 import validateOptions from './validateOptions';
 import validators from './validators';
@@ -59,6 +60,7 @@ export interface Configuration {
   readonly inspectors: LDInspection[];
   readonly credentialType: 'clientSideId' | 'mobileKey';
   readonly getImplementationHooks: (environmentMetadata: LDPluginEnvironmentMetadata) => Hook[];
+  readonly dataSystem?: LDClientDataSystemOptions;
 }
 
 const DEFAULT_POLLING: string = 'https://clientsdk.launchdarkly.com';
@@ -138,6 +140,7 @@ export default class ConfigurationImpl implements Configuration {
   public readonly getImplementationHooks: (
     environmentMetadata: LDPluginEnvironmentMetadata,
   ) => Hook[];
+  public readonly dataSystem?: LDClientDataSystemOptions;
 
   // Allow indexing Configuration by a string
   [index: string]: any;

packages/shared/sdk-client/src/configuration/validators.ts

@@ -35,6 +35,7 @@ const validators: Record<keyof LDOptions, TypeValidator> = {
   hooks: TypeValidators.createTypeArray('Hook[]', {}),
   inspectors: TypeValidators.createTypeArray('LDInspection', {}),
   cleanOldPersistentData: TypeValidators.Boolean,
+  dataSystem: TypeValidators.Object,
 };
 
 export default validators;

packages/shared/sdk-client/src/index.ts

@@ -116,6 +116,14 @@ export { flagEvalPayloadToItemDescriptors } from './datasource/flagEvalMapper';
 export { createDataSourceStatusManager } from './datasource/DataSourceStatusManager';
 export type { DataSourceStatusManager } from './datasource/DataSourceStatusManager';
 
+// FDv2 data system validators and platform defaults.
+export {
+  dataSystemValidators,
+  BROWSER_DATA_SYSTEM_DEFAULTS,
+  MOBILE_DATA_SYSTEM_DEFAULTS,
+  DESKTOP_DATA_SYSTEM_DEFAULTS,
+} from './datasource/LDClientDataSystemOptions';
+
 // FDv2 connection mode type system — internal implementation.
 export type { ModeTable } from './datasource/ConnectionModeConfig';
 export {