otp-number

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

✨ Features

• ✅ Supports digits, uppercase, and lowercase characters
• ✅ Configurable OTP length
• ✅ Works in Node.js and browser (UMD compatible)
• ✅ Zero dependencies
• 🔢 Numeric-only OTP shortcut with otp_number_only(length)

📦 Installation

npm install otp-number

🔧 Usage

const { otp_number, otp_number_only } = require('otp-number');

// Generate a 6-digit OTP with digits, uppercase, and lowercase letters (default) const defaultOTP = otp_number(); console.log(defaultOTP); // Example: "aB3dE9"

// Generate an 8-digit numeric-only OTP using the helper function const numericOTP = otp_number_only(8); console.log(numericOTP); // Example: "12345678"

// Generate a 10-character OTP with only uppercase letters and digits const customOTP = otp_number(10, { digits: true, upperCase: true, lowerCase: false }); console.log(customOTP); // Example: "A1B2C3D4E5"

// Generate a 4-character OTP with only lowercase letters const lowercaseOTP = otp_number(4, { digits: false, upperCase: false, lowerCase: true }); console.log(lowercaseOTP); // Example: "wxyz"

// Attempting to generate an OTP with no character sets enabled will throw an error: try { otp_number(6, { digits: false, upperCase: false, lowerCase: false }); } catch (error) { console.error(error.message); // Output: "At least one character set must be enabled." }

Numeric Only Shortcut

const { otp_number_only } = require('otp-number');
console.log(otp_number_only(6)); // ➤ "920384"

## Browser (UMD)

<script src="dist/otp-generator.umd.js"></script>
<script>
  const otp = OtpGenerator.otp_number(6, { digits: true, upperCase: true });
  console.log("OTP:", otp);
</script>


## ⚙️ API
otp_number(length, options)

Parameter	Type	Default	Description
length	number	6	Length of the OTP
options.digits	boolean	true	Include digits (0-9)
options.upperCase	boolean	false	Include uppercase letters (A-Z)
options.lowerCase	boolean	false	Include lowercase letters (a-z)

## 📌 Example Outputs

otp_number();
// ➤ "729314"

otp_number(6, { digits: true, upperCase: true });
// ➤ "5J8K2Q"

otp_number(4, { lowerCase: true });
// ➤ "kfza"
otp_number_only(length = 6)

A helper function that generates a numeric-only OTP string of the specified length. This is equivalent to calling otp_number(length, { digits: true }).

## 📁 Build (for Browser Support)

Install dev dependencies:

bash
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Edit
npm install --save-dev rollup @rollup/plugin-commonjs @rollup/plugin-node-resolve
Build UMD:

bash
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npx rollup -c

## 🔎 Keywords

otp, otp-number, random otp, otp generator, javascript otp, nodejs otp, one-time password, verification code, auth code, frontend backend otp, browser otp, 2FA