feat: enhance input validation for username and password during signup

Author: LightYagami28

API/server.js

@@ -207,7 +207,7 @@ app.post('/api/signup', async (req, res) => {
     }
 
     // Check if the username contains at least 5 characters
-    if (username.length < 5) {
+    if (String(username).length < 5) {
         const data = {
             "STATUS": "ERROR",
             "MESSAGE": "BAD REQUEST - THE USERNAME HAS LESS THAN 5 CHARACTERS",
@@ -221,7 +221,7 @@ app.post('/api/signup', async (req, res) => {
     }
 
     // Check if the username is more than 20 characters
-    if (username.length > 20) {
+    if (String(username).length > 20) {
         const data = {
             "STATUS": "ERROR",
             "MESSAGE": "BAD REQUEST - THE USERNAME HAS MORE THAN 20 CHARACTERS",
@@ -235,7 +235,7 @@ app.post('/api/signup', async (req, res) => {
     }
 
     // Check if the password contains at least 6 characters
-    if (password.length < 6) {
+    if (String(password).length < 6) {
         const data = {
             "STATUS": "ERROR",
             "MESSAGE": "BAD REQUEST - THE PASSWORD HAS LESS THAN 6 CHARACTERS",
@@ -249,7 +249,7 @@ app.post('/api/signup', async (req, res) => {
     }
 
     // Check if the password is more than 80 characters
-    if (password.length > 80) {
+    if (String(password).length > 80) {
         const data = {
             "STATUS": "ERROR",
             "MESSAGE": "BAD REQUEST - THE PASSWORD HAS MORE THAN 80 CHARACTERS",