expirationDays configuration

src/storages/dataLoader.ts

@@ -1,7 +1,9 @@
 import { PreloadedData } from '../types';
-import { DEFAULT_CACHE_EXPIRATION_IN_MILLIS } from '../utils/constants/browser';
 import { DataLoader, ISegmentsCacheSync, ISplitsCacheSync } from './types';
 
+// This value might be eventually set via a config parameter
+const DEFAULT_CACHE_EXPIRATION_IN_MILLIS = 864000000; // 10 days
+
 /**
  * Factory of client-side storage loader
  *

src/storages/inLocalStorage/index.ts

@@ -50,7 +50,7 @@ export function InLocalStorage(options: SplitIO.InLocalStorageOptions = {}): ISt
       uniqueKeys: impressionsMode === NONE ? new UniqueKeysCacheInMemoryCS() : undefined,
 
       validateCache() {
-        return validateCache(settings, keys, splits, segments, largeSegments);
+        return validateCache(options, settings, keys, splits, segments, largeSegments);
       },
 
       destroy() { },

src/storages/inLocalStorage/validateCache.ts

@@ -1,21 +1,28 @@
 import { ISettings } from '../../types';
-import { DEFAULT_CACHE_EXPIRATION_IN_MILLIS } from '../../utils/constants/browser';
-import { isNaNNumber } from '../../utils/lang';
+import { isFiniteNumber, isNaNNumber } from '../../utils/lang';
 import { getStorageHash } from '../KeyBuilder';
 import { LOG_PREFIX } from './constants';
 import type { SplitsCacheInLocal } from './SplitsCacheInLocal';
 import type { MySegmentsCacheInLocal } from './MySegmentsCacheInLocal';
 import { KeyBuilderCS } from '../KeyBuilderCS';
+import SplitIO from '../../../types/splitio';
 
-function validateExpiration(settings: ISettings, keys: KeyBuilderCS) {
+// milliseconds in a day
+const DEFAULT_CACHE_EXPIRATION_IN_DAYS = 10;
+const MILLIS_IN_A_DAY = 86400000;
+
+function validateExpiration(options: SplitIO.InLocalStorageOptions, settings: ISettings, keys: KeyBuilderCS) {
   const { log } = settings;
 
   // Check expiration
-  const expirationTimestamp = Date.now() - DEFAULT_CACHE_EXPIRATION_IN_MILLIS;
+  const expirationTimestamp = Date.now() - MILLIS_IN_A_DAY * (isFiniteNumber(options.expirationDays) && options.expirationDays >= 1 ? options.expirationDays : DEFAULT_CACHE_EXPIRATION_IN_DAYS);
   let value: string | number | null = localStorage.getItem(keys.buildLastUpdatedKey());
   if (value !== null) {
     value = parseInt(value, 10);
-    if (!isNaNNumber(value) && value < expirationTimestamp) return true;
+    if (!isNaNNumber(value) && value < expirationTimestamp) {
+      log.info(LOG_PREFIX + 'Cache expired. Cleaning up cache');
+      return true;
+    }
   }
 
   // Check hash
@@ -24,7 +31,7 @@ function validateExpiration(settings: ISettings, keys: KeyBuilderCS) {
   const currentStorageHash = getStorageHash(settings);
 
   if (storageHash !== currentStorageHash) {
-    log.info(LOG_PREFIX + 'SDK key, flags filter criteria or flags spec version was modified. Updating cache');
+    log.info(LOG_PREFIX + 'SDK key, flags filter criteria or flags spec version was modified. Cleaning up cache');
     try {
       localStorage.setItem(storageHashKey, currentStorageHash);
     } catch (e) {
@@ -39,9 +46,9 @@ function validateExpiration(settings: ISettings, keys: KeyBuilderCS) {
  * - it has expired, i.e., its `lastUpdated` timestamp is older than the given `expirationTimestamp`
  * - hash has changed, i.e., the SDK key, flags filter criteria or flags spec version was modified
  */
-export function validateCache(settings: ISettings, keys: KeyBuilderCS, splits: SplitsCacheInLocal, segments: MySegmentsCacheInLocal, largeSegments: MySegmentsCacheInLocal): boolean {
+export function validateCache(options: SplitIO.InLocalStorageOptions, settings: ISettings, keys: KeyBuilderCS, splits: SplitsCacheInLocal, segments: MySegmentsCacheInLocal, largeSegments: MySegmentsCacheInLocal): boolean {
 
-  if (validateExpiration(settings, keys)) {
+  if (validateExpiration(options, settings, keys)) {
     splits.clear();
     segments.clear();
     largeSegments.clear();

src/utils/lang/index.ts

@@ -120,7 +120,7 @@ export function isBoolean(val: any): boolean {
  * Unlike `Number.isFinite`, it also tests Number object instances.
  * Unlike global `isFinite`, it returns false if the value is not a number or Number object instance.
  */
-export function isFiniteNumber(val: any): boolean {
+export function isFiniteNumber(val: any): val is number {
   if (val instanceof Number) val = val.valueOf();
   return typeof val === 'number' ?
     Number.isFinite ? Number.isFinite(val) : isFinite(val) :

types/splitio.d.ts

@@ -906,6 +906,18 @@ declare namespace SplitIO {
      * @defaultValue `'SPLITIO'`
      */
     prefix?: string;
+    /**
+     * Number of days before cached data expires if it was not updated. If cache expires, it is cleared on initialization.
+     *
+     * @defaultValue `10`
+     */
+    expirationDays?: number;
+    /**
+     * Optional settings to clear the cache. If set to `true`, the SDK clears the cached data on initialization, unless the cache was cleared within the last 24 hours.
+     *
+     * @defaultValue `false`
+     */
+    clearOnInit?: boolean;
   }
   /**
    * Storage for asynchronous (consumer) SDK.
@@ -1229,11 +1241,23 @@ declare namespace SplitIO {
        */
       type?: BrowserStorage;
       /**
-       * Optional prefix to prevent any kind of data collision between SDK versions.
+       * Optional prefix to prevent any kind of data collision between SDK versions when using 'LOCALSTORAGE'.
        *
        * @defaultValue `'SPLITIO'`
        */
       prefix?: string;
+      /**
+       * Optional settings for the 'LOCALSTORAGE' storage type. It specifies the number of days before cached data expires if it was not updated. If cache expires, it is cleared on initialization.
+       *
+       * @defaultValue `10`
+       */
+      expirationDays?: number;
+      /**
+       * Optional settings for the 'LOCALSTORAGE' storage type. If set to `true`, the SDK clears the cached data on initialization, unless the cache was cleared within the last 24 hours.
+       *
+       * @defaultValue `false`
+       */
+      clearOnInit?: boolean;
     };
   }
   /**