Username Validator Tool

A lightweight and easy-to-use npm package to validate usernames based on configurable rules. This tool checks for length, allowed characters, and uniqueness, making it perfect for user registration systems.

Features

• ✅ Validate username length (default: 3-15 characters).
• ✅ Ensure usernames contain only letters, numbers, and underscores (_).
• ✅ Check if a username is already taken.
• ✅ Detailed validation messages for better user feedback.

Installation

Install the package via npm:

npm install username-validator-tool

API

validateUsername(username, existingUsernames)

Parameters:

• username (string): The username to validate.
• existingUsernames (array): List of existing usernames to check for uniqueness.

Returns: An object with the following structure:

  valid: Boolean, // true if valid, false if invalid
  message: String, // Success message (if valid)
  errors: Array    // List of error messages (if invalid)

Examples

1. Valid Username

validateUsername('valid_user', ['john_doe', 'jane123']);
// Output:
// { valid: true, message: 'Username is valid!' }

2. Username too Short

Output:
// { valid: false, errors: ['Username must be between 3 and 15 characters.'] }

3. Invalid Characters

// Output:
// { valid: false, errors: ['Username can only contain letters, numbers, and underscores.'] }

4. Username Already Taken

validateUsername('john_doe', ['john_doe', 'jane123']);
// Output:
// { valid: false, errors: ['Username is already taken.'] }