Add subscription interval to ping params

src/classes/Metrics.js

@@ -371,6 +371,8 @@ class Metrics {
 			// New parameter for Ghostery 8.5.2
 			// Hub Promo variant
 			`&hp=${encodeURIComponent(Metrics._getHubPromoVariant().toString())}`;
+			// Subscription Interval
+			`&si=${encodeURIComponent(Metrics._getSubscriptionInterval().toString())}`;
 
 		if (CAMPAIGN_METRICS.includes(type)) {
 			// only send campaign attribution when necessary
@@ -550,6 +552,27 @@ class Metrics {
 		}
 	}
 
+	/**
+	 * Get the Int associated with the users subscription interval
+	 * @private
+	 * @return {number} String associated with the users subscription interval
+	 */
+	static _getSubscriptionInterval() {
+		const subscriptionInterval = conf && conf.account && conf.account.subscriptionData && conf.account.subscriptionData.planInterval;
+
+		if (subscriptionInterval) {
+			switch (subscriptionInterval) {
+				case 'month':
+					return 1;
+				case 'year':
+					return 2;
+				default:
+					return 0;
+			}
+		}
+		return 0;
+	}
+
 	/**
 	 * Calculate remaining scheduled time for a ping
 	 *