URL filter functionality.

lib/url.js

@@ -13,3 +13,18 @@ export function getDomainName(str) {
     return str;
   }
 }
+
+export function getQueryString(params) {
+  const map = Object.keys(params).reduce((arr, key) => {
+    if (params[key] !== undefined) {
+      return arr.concat(`${key}=${encodeURIComponent(params[key])}`);
+    }
+    return arr;
+  }, []);
+
+  if (map.length) {
+    return `?${map.join('&')}`;
+  }
+
+  return '';
+}