refactor: change backend to typescript and update types and variables accordingly

backend/services/helperFuncs.ts

@@ -1,9 +1,14 @@
-export const returnErrorCode = (errorKey) => {
+import type {ErrorCode} from "../misc/types.ts";
+
+export const returnErrorCode = (errorKey: ErrorCode) => {
     if (!Array.isArray(errorKey) || errorKey.length < 2) {
         return false;
     }
 
-    return {code: errorKey[0], message: errorKey[1], data: null};
-};
-
-export default returnErrorCode;
+    return {
+        success: false,
+        code: errorKey[0],
+        data: null,
+        message: errorKey[1]
+    }
+};