diff --git a/back-end/src/controllers/members.controller.ts b/back-end/src/controllers/members.controller.ts
index 8280aa6..b61cbf6 100644
--- a/back-end/src/controllers/members.controller.ts
+++ b/back-end/src/controllers/members.controller.ts
@@ -24,7 +24,7 @@ async function getMember(idOrName: number | string): Promise<Either<Member, stri
 
 async function createMember(name: string, passwd: string): Promise<Either<Member, string>> {
     const gettingMember = await getMember(name);
-    if (!gettingMember.hasError) {
+    if (!gettingMember.hasRight) {
         return eitherRight("Already in database.");
     }
     const client = new_client();
@@ -62,10 +62,10 @@ const register = (req: Request, res: Response) => {
             }
 
             const member: Either<Member, string> = await createMember(name, hash);
-            if (member.hasError)
-                res.send(member.error);
+            if (member.hasRight)
+                res.send(member.right);
             else
-                res.send(userAdapter(member.value));
+                res.send(userAdapter(member.left));
         });
     });
 }
diff --git a/back-end/src/utils/utils.ts b/back-end/src/utils/utils.ts
index 9a75651..abbed21 100644
--- a/back-end/src/utils/utils.ts
+++ b/back-end/src/utils/utils.ts
@@ -1,15 +1,15 @@
 type Either<T, U> = {
-    hasError: boolean,
-    value: T,
-    error: U
+    hasRight: boolean,
+    left: T,
+    right: U
 };
 
-function eitherLeft<T, U>(val: T): Either<T, U> {
-    return { hasError: false, value: val, error: undefined };
+function eitherLeft<T, U>(left: T): Either<T, U> {
+    return { hasRight: false, left: left, right: undefined };
 }
 
-function eitherRight<T, U>(error: U): Either<T, U> {
-    return { hasError: true, value: undefined, error: error };
+function eitherRight<T, U>(right: U): Either<T, U> {
+    return { hasRight: true, left: undefined, right: right };
 }
 
 export { Either, eitherLeft, eitherRight };