feat: create EppoPrecomputedClient

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@eppo/js-client-sdk-common",
-  "version": "4.4.0",
+  "version": "4.5.0",
   "description": "Eppo SDK for client-side JavaScript applications (base for both web and react native)",
   "main": "dist/index.js",
   "files": [

src/api-endpoints.ts

@@ -1,8 +1,13 @@
-import { BASE_URL as DEFAULT_BASE_URL, UFC_ENDPOINT, BANDIT_ENDPOINT } from './constants';
-import { IQueryParams } from './http-client';
+import {
+  BASE_URL as DEFAULT_BASE_URL,
+  UFC_ENDPOINT,
+  BANDIT_ENDPOINT,
+  PRECOMPUTED_FLAGS_ENDPOINT,
+} from './constants';
+import { IQueryParams, IQueryParamsWithSubject } from './http-client';
 
 interface IApiEndpointsParams {
-  queryParams?: IQueryParams;
+  queryParams?: IQueryParams | IQueryParamsWithSubject;
   baseUrl?: string;
 }
 
@@ -27,4 +32,8 @@ export default class ApiEndpoints {
   banditParametersEndpoint(): URL {
     return this.endpoint(BANDIT_ENDPOINT);
   }
+
+  precomputedFlagsEndpoint(): URL {
+    return this.endpoint(PRECOMPUTED_FLAGS_ENDPOINT);
+  }
 }

src/assignment-logger.spec.ts

@@ -1,5 +1,6 @@
 import { IAssignmentEvent } from './assignment-logger';
 import { AllocationEvaluationCode } from './flag-evaluation-details-builder';
+import { FormatEnum } from './interfaces';
 
 describe('IAssignmentEvent', () => {
   it('should allow adding arbitrary fields', () => {
@@ -11,6 +12,7 @@ describe('IAssignmentEvent', () => {
       subject: 'subject_123',
       timestamp: new Date().toISOString(),
       subjectAttributes: { age: 25, country: 'USA' },
+      format: FormatEnum.SERVER,
       holdoutKey: 'holdout_key_123',
       evaluationDetails: {
         environmentName: 'Test',

src/assignment-logger.ts

@@ -50,9 +50,14 @@ export interface IAssignmentEvent {
   metaData?: Record<string, unknown>;
 
   /**
-   * The flag evaluation details
+   * The format of the flag.
    */
-  evaluationDetails: IFlagEvaluationDetails;
+  format: string;
+
+  /**
+   * The flag evaluation details. Null if the flag was precomputed.
+   */
+  evaluationDetails: IFlagEvaluationDetails | null;
 }
 
 /**

src/client/eppo-client.ts

@@ -871,7 +871,13 @@ export default class EppoClient {
         'FLAG_UNRECOGNIZED_OR_DISABLED',
         `Unrecognized or disabled flag: ${flagKey}`,
       );
-      return noneResult(flagKey, subjectKey, subjectAttributes, flagEvaluationDetails);
+      return noneResult(
+        flagKey,
+        subjectKey,
+        subjectAttributes,
+        flagEvaluationDetails,
+        configDetails.configFormat,
+      );
     }
 
     if (!checkTypeMatch(expectedVariationType, flag.variationType)) {
@@ -881,7 +887,13 @@ export default class EppoClient {
           'TYPE_MISMATCH',
           errorMessage,
         );
-        return noneResult(flagKey, subjectKey, subjectAttributes, flagEvaluationDetails);
+        return noneResult(
+          flagKey,
+          subjectKey,
+          subjectAttributes,
+          flagEvaluationDetails,
+          configDetails.configFormat,
+        );
       }
       throw new TypeError(errorMessage);
     }
@@ -893,7 +905,13 @@ export default class EppoClient {
         'FLAG_UNRECOGNIZED_OR_DISABLED',
         `Unrecognized or disabled flag: ${flagKey}`,
       );
-      return noneResult(flagKey, subjectKey, subjectAttributes, flagEvaluationDetails);
+      return noneResult(
+        flagKey,
+        subjectKey,
+        subjectAttributes,
+        flagEvaluationDetails,
+        configDetails.configFormat,
+      );
     }
 
     const result = this.evaluator.evaluateFlag(
@@ -941,9 +959,8 @@ export default class EppoClient {
     return {
       configFetchedAt: this.flagConfigurationStore.getConfigFetchedAt() ?? '',
       configPublishedAt: this.flagConfigurationStore.getConfigPublishedAt() ?? '',
-      configEnvironment: this.flagConfigurationStore.getEnvironment() ?? {
-        name: '',
-      },
+      configEnvironment: this.flagConfigurationStore.getEnvironment() ?? { name: '' },
+      configFormat: this.flagConfigurationStore.getFormat() ?? '',
     };
   }
 
@@ -1062,12 +1079,13 @@ export default class EppoClient {
   }
 
   private maybeLogAssignment(result: FlagEvaluation) {
-    const { flagKey, subjectKey, allocationKey, subjectAttributes, variation } = result;
+    const { flagKey, format, subjectKey, allocationKey, subjectAttributes, variation } = result;
     const event: IAssignmentEvent = {
       ...(result.extraLogging ?? {}),
       allocation: allocationKey ?? null,
       experiment: allocationKey ? `${flagKey}-${allocationKey}` : null,
       featureFlag: flagKey,
+      format,
       variation: variation?.key ?? null,
       subject: subjectKey,
       timestamp: new Date().toISOString(),