clean up getUrlQueryParam

Remove dead getUrlQueryParam in SDK code, and also improve
implementation in example project

express_webpack/amp/index.html

@@ -6,16 +6,8 @@
     const SERVICE_WORKER_PATH = "push/onesignal/";
 
     function getUrlQueryParam(name) {
-        var url = window.location.href;
-        // This is just to avoid case sensitiveness
-        url = url.toLowerCase();
-        // This is just to avoid case sensitiveness for query parameter name
-        name = name.replace(/[\[\]]/g, "\\$&").toLowerCase();
-        var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
-            results = regex.exec(url);
-        if (!results) return null;
-        if (!results[2]) return '';
-        return decodeURIComponent(results[2].replace(/\+/g, " "));
+      const urlParams = new URLSearchParams(window.location.search);
+      return urlParams.get(name);
     }
 
     const appId = getUrlQueryParam('app_id');

express_webpack/index.html

@@ -17,16 +17,8 @@
     let showEventAlertToggleSetting = false;
 
     function getUrlQueryParam(name) {
-        var url = window.location.href;
-        // This is just to avoid case sensitiveness
-        url = url.toLowerCase();
-        // This is just to avoid case sensitiveness for query parameter name
-        name = name.replace(/[\[\]]/g, "\\$&").toLowerCase();
-        var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
-            results = regex.exec(url);
-        if (!results) return null;
-        if (!results[2]) return '';
-        return decodeURIComponent(results[2].replace(/\+/g, " "));
+      const urlParams = new URLSearchParams(window.location.search);
+      return urlParams.get(name);
     }
 
     const appId = getUrlQueryParam('app_id');

src/shared/utils/utils.ts

@@ -273,17 +273,6 @@ export function isValidUuid(uuid: string) {
   return OneSignalUtils.isValidUuid(uuid);
 }
 
-export function getUrlQueryParam(name: string) {
-  let url = window.location.href;
-  url = url.toLowerCase(); // This is just to avoid case sensitiveness
-  name = name.replace(/[[\]]/g, '\\$&').toLowerCase(); // This is just to avoid case sensitiveness for query parameter name
-  const regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
-    results = regex.exec(url);
-  if (!results) return null;
-  if (!results[2]) return '';
-  return decodeURIComponent(results[2].replace(/\+/g, ' '));
-}
-
 /**
  * Wipe OneSignal-related IndexedDB data on the "correct" computed origin, but OneSignal must be initialized first to use.
  */