Removed the need for extra variable creation

app/assets/javascripts/boards/boards_bundle.js

@@ -65,11 +65,10 @@ $(() => {
     created () {
       if (this.milestoneTitle) {
         const milestoneTitleParam = `milestone_title=${this.milestoneTitle}`;
-        let splitPath = Store.filter.path.split('&')
-          .filter(param => param.match(/^milestone_title=(.*)$/g) === null);
-
-        splitPath = [milestoneTitleParam].concat(splitPath);
-        Store.filter.path = splitPath.join('&');
+        
+        Store.filter.path = [milestoneTitleParam].concat(
+          Store.filter.path.split('&').filter(param => param.match(/^milestone_title=(.*)$/g) === null)
+        ).join('&');
 
         Store.updateFiltersUrl(true);
       }