commonutil-core

A comprehensive utility library written in TypeScript that provides common string manipulation, text formatting, and validation functions for modern JavaScript/TypeScript applications.

Features

• 🔧 String Utilities: Capitalize text, extract digits, truncate with ellipsis
• 💳 Card Validation: Validate credit card expiry dates
• 📊 Number Formatting: Format numbers in Indian or International format
• 🎯 TypeScript Support: Fully typed with comprehensive type definitions
• ✅ Well Tested: 100% test coverage with Jest
• 📦 Zero Dependencies: Lightweight with no external dependencies

Installation

npm install commonutil-core

Usage

Import Functions

import { uCFirst } from "commonutil-core";

String Utilities

uCFirst(text: string): string

Capitalizes the first letter of a string and trims whitespace.

import { uCFirst } from "commonutil-core";

console.log(uCFirst("hello world")); // 'Hello world'
console.log(uCFirst("  javascript  ")); // 'Javascript'

// Throws error for invalid input
uCFirst(""); // throws "String not provided"
uCFirst(123); // throws "Not a string"

getDigits(text: string): string

Extracts only digits from a given string.

import { getDigits } from "commonutil-core";

console.log(getDigits("abc123def456")); // '123456'
console.log(getDigits("Phone: +1-555-123-4567")); // '15551234567'
console.log(getDigits("No digits here!")); // ''

// Throws error for invalid input
getDigits(""); // throws "String not provided"
getDigits(null); // throws "Not a string"

getMaxText(text: string, limit?: number): string

Truncates text to specified length with ellipsis if necessary. Default limit is 10 characters.

import { getMaxText } from "commonutil-core";

console.log(getMaxText("Hello World")); // 'Hello Worl...'
console.log(getMaxText("Short")); // 'Short'
console.log(getMaxText("Long text here", 8)); // 'Long tex...'
console.log(getMaxText("Exactly 5", 5)); // 'Exactly 5'

// Throws error for invalid input
getMaxText(""); // throws "Invalid or No string provided"
getMaxText(null); // throws "Invalid or No string provided"

Number Formatting

formatDigits(digits: string, format?: 'indian' | 'international'): string

Formats digit strings in Indian or International number format.

import { formatDigits } from "commonutil-core";

// Indian format (default): adds commas in Indian style
console.log(formatDigits("1234567")); // '12,34,567'
console.log(formatDigits("123456789")); // '12,34,56,789'

// International format: adds commas every 3 digits
console.log(formatDigits("1234567", "international")); // '1,234,567'
console.log(formatDigits("123456789", "international")); // '123,456,789'

// Throws error for invalid input
formatDigits("12a34"); // throws "Not all characters are digits"
formatDigits(""); // throws "No digits provided"

Card Validation

isValidExpiryForCard(expiry: string): { status: boolean, error: string | null }

Validates credit card expiry date in MM/YY format and checks if it's not expired.

import { isValidExpiryForCard } from "commonutil-core";

// Valid future date
console.log(isValidExpiryForCard("12/25"));
// { status: true, error: null }

// Invalid format
console.log(isValidExpiryForCard("13/25"));
// { status: false, error: 'Invalid format. Should be like "01/26" or "11/30" in "MM/YY"' }

// Expired date
console.log(isValidExpiryForCard("01/20"));
// { status: false, error: 'Already Expired' }

// Invalid input
console.log(isValidExpiryForCard(""));
// { status: false, error: 'Input not provided' }

Validation Rules:

• Must be exactly 5 characters in MM/YY format
• Month must be 01-12
• Year must be 2-digit (interpreted as 20XX)
• Date must be in the future
• Handles different month lengths correctly

API Reference

| Function | Parameters | Returns | Description | | ---------------------- | --------------------------------- | ---------------------------------------- | ------------------------------------------- | | uCFirst | text: string | string | Capitalizes first letter and trims | | getDigits | text: string | string | Extracts only digits from string | | getMaxText | text: string, limit?: number | string | Truncates with ellipsis (default limit: 10) | | formatDigits | digits: string, format?: string | string | Formats numbers (indian/international) | | isValidExpiryForCard | expiry: string | {status: boolean, error: string\|null} | Validates card expiry date |

Error Handling

All functions include proper error handling and will throw descriptive error messages for invalid inputs:

• Empty strings or whitespace-only strings
• Non-string inputs
• Invalid formats
• Out-of-range values

TypeScript Support

This library is written in TypeScript and includes comprehensive type definitions. You'll get full IntelliSense support and type checking in TypeScript projects.

// TypeScript usage with full type safety
const result: string = uCFirst("hello");
const validation: { status: boolean; error: string | null } =
  isValidExpiryForCard("12/25");

Development

Building

npm run build

Testing

npm test

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Changelog

v1.0.7

• Current stable version
• All core utilities implemented and tested

Author

Mahesh - GitHub

Support

If you encounter any issues or have questions, please file an issue on the GitHub issue tracker.