Include URL query param in epics path when params are present

ee/app/assets/javascripts/roadmap/index.js

@@ -27,6 +27,7 @@ export default () => {
     },
     data() {
       const dataset = this.$options.el.dataset;
+      const filterQueryString = window.location.search.substring(1);
 
       // Construct Epic API path to include
       // `start_date` & `end_date` query params to get list of
@@ -36,7 +37,11 @@ export default () => {
       const end = timeframe[TIMEFRAME_LENGTH - 1];
       const startDate = `${start.getFullYear()}-${start.getMonth() + 1}-${start.getDate()}`;
       const endDate = `${end.getFullYear()}-${end.getMonth() + 1}-${end.getDate()}`;
-      const epicsPath = `${dataset.epicsPath}?start_date=${startDate}&end_date=${endDate}`;
+      let epicsPath = `${dataset.epicsPath}?start_date=${startDate}&end_date=${endDate}`;
+
+      if (filterQueryString) {
+        epicsPath += `&${filterQueryString}`;
+      }
 
       const store = new RoadmapStore(parseInt(dataset.groupId, 0), timeframe);
       const service = new RoadmapService(epicsPath);