feat: allow to calc sub state in the future

lib/index.js

@@ -107,6 +107,14 @@ class Subscriptions {
         }
 
         await this._storage.put(ids, subscriptionModel)
+
+        return {
+            passthrough: {
+                v1: {
+                    ids
+                }
+            }
+        }
     }
 
     /**
@@ -208,19 +216,21 @@ class Subscriptions {
     /**
      * 
      * @param {Object} subscription 
+     * @param {Date} [atDate=new Date()] date for the calculation  
      * @returns {boolean} true subscription is active
      */
-    async isSubscriptionActive(subscription) {
-        return this._isOneOfSubscriptionsActive([subscription])
+    async isSubscriptionActive(subscription, atDate = new Date()) {
+        return this._isOneOfSubscriptionsActive([subscription], atDate)
     }
 
     /**
      * 
      * @param {Array} subscriptions
+     * @param {Date} [atDate=new Date()] date for the calculation  
      * @returns {boolean} true if an active subscription was given
      */
-    async _isOneOfSubscriptionsActive(subscriptions) {
-        const now = Date.now()
+    async _isOneOfSubscriptionsActive(subscriptions, atDate) {
+        const now = atDate.getTime()
 
         const allStatus = subscriptions.map(subscription => {
             // filter all status object that have a start date in the past