diff --git a/superset-frontend/src/setup/setupClient.js b/superset-frontend/src/setup/setupClient.ts
similarity index 83%
rename from superset-frontend/src/setup/setupClient.js
rename to superset-frontend/src/setup/setupClient.ts
index 0f1a039f679..11f3f6a1a28 100644
--- a/superset-frontend/src/setup/setupClient.js
+++ b/superset-frontend/src/setup/setupClient.ts
@@ -20,14 +20,16 @@ import { SupersetClient, logging } from '@superset-ui/core';
 import parseCookie from 'src/utils/parseCookie';
 
 export default function setupClient() {
-  const csrfNode = document.querySelector('#csrf_token');
-  const csrfToken = csrfNode ? csrfNode.value : null;
+  const csrfNode = document.querySelector<HTMLInputElement>('#csrf_token');
+  const csrfToken = csrfNode?.value;
 
   // when using flask-jwt-extended csrf is set in cookies
   const cookieCSRFToken = parseCookie().csrf_access_token || '';
 
   SupersetClient.configure({
-    protocol: (window.location && window.location.protocol) || '',
+    protocol: ['http:', 'https:'].includes(window?.location?.protocol)
+      ? (window?.location?.protocol as 'http:' | 'https:')
+      : undefined,
     host: (window.location && window.location.host) || '',
     csrfToken: csrfToken || cookieCSRFToken,
   })
diff --git a/superset-frontend/src/setup/setupFormatters.js b/superset-frontend/src/setup/setupFormatters.ts
similarity index 100%
rename from superset-frontend/src/setup/setupFormatters.js
rename to superset-frontend/src/setup/setupFormatters.ts
diff --git a/superset-frontend/src/setup/setupPluginsExtra.js b/superset-frontend/src/setup/setupPluginsExtra.ts
similarity index 100%
rename from superset-frontend/src/setup/setupPluginsExtra.js
rename to superset-frontend/src/setup/setupPluginsExtra.ts
diff --git a/superset-frontend/src/utils/errorMessages.js b/superset-frontend/src/utils/errorMessages.ts
similarity index 100%
rename from superset-frontend/src/utils/errorMessages.js
rename to superset-frontend/src/utils/errorMessages.ts