Import crypto for node environment

src/index.ts

@@ -34,6 +34,7 @@ import {
 import { HybridConfigurationStore } from './configuration-store/hybrid.store';
 import { MemoryStore, MemoryOnlyConfigurationStore } from './configuration-store/memory.store';
 import * as constants from './constants';
+import { decodePrecomputedFlag } from './decoding';
 import BatchEventProcessor from './events/batch-event-processor';
 import { BoundedEventQueue } from './events/bounded-event-queue';
 import DefaultEventDispatcher, {
@@ -47,6 +48,7 @@ import NamedEventQueue from './events/named-event-queue';
 import NetworkStatusListener from './events/network-status-listener';
 import HttpClient from './http-client';
 import { PrecomputedFlag, Flag, ObfuscatedFlag, VariationType, FormatEnum } from './interfaces';
+import { setSaltOverrideForTests } from './obfuscation';
 import {
   AttributeType,
   Attributes,
@@ -125,4 +127,8 @@ export {
   IConfigurationWire,
   IPrecomputedConfigurationResponse,
   PrecomputedFlag,
+
+  // Test helpers
+  setSaltOverrideForTests,
+  decodePrecomputedFlag,
 };

src/obfuscation.ts

@@ -1,8 +1,26 @@
 import base64 = require('js-base64');
 import * as SparkMD5 from 'spark-md5';
 
+import { logger } from './application-logger';
 import { PrecomputedFlag } from './interfaces';
 
+// Import randomBytes according to the environment
+let getRandomValues: (length: number) => Uint8Array;
+if (typeof window !== 'undefined' && window.crypto) {
+  // Browser environment
+  getRandomValues = (length: number) => window.crypto.getRandomValues(new Uint8Array(length));
+} else {
+  // Node.js environment
+  import('crypto')
+    .then((crypto) => {
+      getRandomValues = (length: number) => new Uint8Array(crypto.randomBytes(length));
+      return;
+    })
+    .catch((error) => {
+      logger.error('Failed to load crypto module:', error);
+    });
+}
+
 export function getMD5Hash(input: string, salt = ''): string {
   return new SparkMD5().append(salt).append(input).end();
 }
@@ -49,7 +67,5 @@ export function setSaltOverrideForTests(salt: Uint8Array | null) {
 }
 
 export function generateSalt(length = 16): string {
-  return base64.fromUint8Array(
-    saltOverrideBytes ? saltOverrideBytes : crypto.getRandomValues(new Uint8Array(length)),
-  );
+  return base64.fromUint8Array(saltOverrideBytes ? saltOverrideBytes : getRandomValues(length));
 }

webpack.config.js

@@ -19,6 +19,9 @@ module.exports = {
   },
   resolve: {
     extensions: ['.tsx', '.ts', '.js'],
+    fallback: {
+      crypto: false, // Exclude crypto module in the browser bundle
+    },
   },
   output: {
     filename: 'eppo-sdk.js',