otp-number/index.js

> 🔐 A lightweight and flexible JavaScript library to generate random OTPs (One-Time Passwords) for use in both frontend and backend applications.

function otp_number(
  length = 6,
  options = { digits: true, upperCase: false, lowerCase: false }
) {
  const sets = {
    digits: "0123456789",
    upperCase: "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
    lowerCase: "abcdefghijklmnopqrstuvwxyz",
  };

  let characters = "";
  if (options.digits) characters += sets.digits;
  if (options.upperCase) characters += sets.upperCase;
  if (options.lowerCase) characters += sets.lowerCase;

  if (!characters)
    throw new Error("At least one character set must be enabled.");

  let otp = "";
  for (let i = 0; i < length; i++) {
    otp += characters.charAt(Math.floor(Math.random() * characters.length));
  }

  return otp;
}

// 👇 New helper for numeric-only OTPs
function otp_number_only(length = 6) {
  return otp_number(length, { digits: true });
}

module.exports = { otp_number, otp_number_only };