feat: enable dynamic digit range for OTP generator

Author: Rahad-Ullah

src/app/modules/auth/auth.service.ts

@@ -89,7 +89,7 @@ const forgetPasswordToDB = async (email: string) => {
   }
 
   //send mail
-  const otp = generateOTP();
+  const otp = generateOTP(6);
   const value = {
     otp,
     email: isExistUser.email,

src/app/modules/user/user.service.ts

@@ -18,7 +18,7 @@ const createUserToDB = async (payload: Partial<IUser>): Promise<IUser> => {
   }
 
   //send email
-  const otp = generateOTP();
+  const otp = generateOTP(6);
   const values = {
     name: createUser.name,
     otp: otp,

src/util/generateOTP.ts

@@ -1,5 +1,8 @@
-const generateOTP = () => {
-  return Math.floor(Math.random() * (9999 - 1000 + 1) + 1000);
+const generateOTP = (digitLength: number) => {
+  const min = Math.pow(10, digitLength - 1);
+  const max = Math.pow(10, digitLength) - 1;
+
+  return Math.floor(Math.random() * (max - min + 1) + min);
 };
 
-export default generateOTP;
+export default generateOTP;