// Generate numeric OTP
function generateOTP(length = 6) {
  const digits = '0123456789';
  let otp = '';
  
  for (let i = 0; i < length; i++) {
    otp += digits[Math.floor(Math.random() * 10)];
  }
  
  return otp;
}

// Generate alphanumeric OTP
function generateAlphaNumericOTP(length = 8) {
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
  let otp = '';
  
  for (let i = 0; i < length; i++) {
    otp += chars[Math.floor(Math.random() * chars.length)];
  }
  
  return otp;
}

console.log(generateOTP(6)); // 123456
console.log(generateAlphaNumericOTP(8)); // A7B9K2M8

import secrets
import string

def generate_numeric_otp(length=6):
    """Generate numeric OTP"""
    return ''.join(secrets.choice(string.digits) for _ in range(length))

def generate_alphanumeric_otp(length=8):
    """Generate alphanumeric OTP"""
    chars = string.ascii_uppercase + string.digits
    return ''.join(secrets.choice(chars) for _ in range(length))

def generate_custom_otp(charset, length):
    """Generate OTP with custom character set"""
    return ''.join(secrets.choice(charset) for _ in range(length))

# Examples
print(generate_numeric_otp(6))      # 123456
print(generate_alphanumeric_otp(8)) # A7B9K2M8
print(generate_custom_otp('ABCDEF0123456789', 10)) # Custom hex-like