Text Case Converter

A comprehensive TypeScript/JavaScript library for text case conversion with regex-based transformation capabilities.

Features

• 🔄 Multiple Case Types: Convert between camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, Title Case, Sentence case, UPPERCASE, and lowercase
• 🎯 Regex Support: Advanced text transformations using custom regex patterns
• 🔍 Case Detection: Automatically detect the case type of input text
• 📦 TypeScript Support: Full TypeScript definitions included
• 🧪 Well Tested: Comprehensive test suite with 100% coverage
• 🚀 Zero Dependencies: Lightweight with no external dependencies
• 🛠️ Flexible Options: Customizable separators, whitespace preservation, and word boundary patterns

Installation

npm install text-case-converter

Quick Start

import { TextCaseConverter } from 'text-case-converter';

// Basic case conversion
TextCaseConverter.convert('hello world', 'camel');     // 'helloWorld'
TextCaseConverter.convert('hello world', 'pascal');    // 'HelloWorld'
TextCaseConverter.convert('hello world', 'snake');     // 'hello_world'
TextCaseConverter.convert('hello world', 'kebab');     // 'hello-world'

// Convert to all case types at once
const allCases = TextCaseConverter.convertToAll('hello world');
console.log(allCases);
// {
//   camel: 'helloWorld',
//   pascal: 'HelloWorld',
//   snake: 'hello_world',
//   kebab: 'hello-world',
//   constant: 'HELLO_WORLD',
//   title: 'Hello World',
//   sentence: 'Hello world',
//   upper: 'HELLO WORLD',
//   lower: 'hello world'
// }

// Detect case type
TextCaseConverter.detectCase('helloWorld');    // 'camel'
TextCaseConverter.detectCase('HelloWorld');    // 'pascal'
TextCaseConverter.detectCase('hello_world');   // 'snake'

API Reference

TextCaseConverter

convert(text: string, caseType: CaseType, options?: ConversionOptions): string

Convert text to the specified case type.

Parameters:

• text - The input text to convert
• caseType - Target case type ('camel', 'pascal', 'snake', 'kebab', 'constant', 'title', 'sentence', 'upper', 'lower')
• options - Optional conversion options

Example:

TextCaseConverter.convert('hello world', 'camel', {
  preserveWhitespace: true,
  separator: '_'
});

convertBatch(texts: string[], caseType: CaseType, options?: ConversionOptions): string[]

Convert multiple texts to the same case type.

const texts = ['hello world', 'foo bar', 'test case'];
TextCaseConverter.convertBatch(texts, 'camel');
// ['helloWorld', 'fooBar', 'testCase']

convertToAll(text: string, options?: ConversionOptions): Record<CaseType, string>

Convert text to all supported case types.

detectCase(text: string): CaseType | 'mixed' | 'unknown'

Detect the case type of input text.

regexTransform(text: string, options: RegexTransformOptions): string

Apply regex-based transformation to text.

TextCaseConverter.regexTransform('hello world', {
  pattern: /world/g,
  replacement: 'universe'
});
// 'hello universe'

RegexTransformer

Advanced regex-based text transformations.

Predefined Transformations

import { RegexTransformer } from 'text-case-converter';

// Normalize whitespace
RegexTransformer.transformations.normalizeWhitespace('hello    world');
// 'hello world'

// Remove special characters
RegexTransformer.transformations.removeSpecialChars('hello@#$world!');
// 'helloworld'

// Extract words
RegexTransformer.transformations.extractWords('hello, world! 123');
// ['hello', 'world', '123']

// Mask emails
RegexTransformer.transformations.maskEmails('Contact [email protected]');
// 'Contact [EMAIL]'

// Format phone numbers
RegexTransformer.transformations.formatPhoneNumbers('Call 1234567890');
// 'Call (123) 456-7890'

// Split camelCase
RegexTransformer.transformations.splitCamelCase('helloWorldTest');
// 'hello World Test'

Custom Patterns

// Use predefined patterns
RegexTransformer.patterns.email;           // Email regex pattern
RegexTransformer.patterns.url;             // URL regex pattern
RegexTransformer.patterns.phone;           // Phone number pattern
RegexTransformer.patterns.camelCaseBoundaries; // camelCase boundaries

// Custom transformation
RegexTransformer.transform('ABC123DEF456', {
  pattern: /([A-Z]+)(\d+)/g,
  replacement: '$1-$2'
});
// 'ABC-123DEF-456'

Individual Converters

You can also import and use individual converter classes:

import { CaseConverter } from 'text-case-converter';

CaseConverter.toCamelCase('hello world');    // 'helloWorld'
CaseConverter.toPascalCase('hello world');   // 'HelloWorld'
CaseConverter.toSnakeCase('hello world');    // 'hello_world'
CaseConverter.toKebabCase('hello world');    // 'hello-world'
CaseConverter.toConstantCase('hello world'); // 'HELLO_WORLD'
CaseConverter.toTitleCase('hello world');    // 'Hello World'
CaseConverter.toSentenceCase('hello world'); // 'Hello world'
CaseConverter.toUpperCase('hello world');    // 'HELLO WORLD'
CaseConverter.toLowerCase('HELLO WORLD');    // 'hello world'

Configuration Options

ConversionOptions

interface ConversionOptions {
  separator?: string;           // Custom separator for words
  preserveWhitespace?: boolean; // Preserve leading/trailing whitespace
  wordBoundaryPattern?: RegExp; // Custom word boundary pattern
}

RegexTransformOptions

interface RegexTransformOptions {
  pattern: RegExp;              // Regex pattern to match
  replacement: string | ((match: string, ...args: any[]) => string);
  global?: boolean;             // Apply transformation globally
}

Advanced Examples

Custom Word Boundaries

TextCaseConverter.convert('hello123world', 'camel', {
  wordBoundaryPattern: /\d+/  // Split on numbers
});
// Result depends on custom pattern

Preserve Whitespace

TextCaseConverter.convert('  hello world  ', 'camel', {
  preserveWhitespace: true
});
// '  helloWorld  '

Complex Regex Transformations

// Convert currency format
TextCaseConverter.regexTransform('price: $10.50', {
  pattern: /\$(\d+)\.(\d+)/g,
  replacement: (match, dollars, cents) => {
    const total = parseInt(dollars) * 100 + parseInt(cents);
    return `${total} cents`;
  }
});
// 'price: 1050 cents'

Chaining Transformations

let text = '[email protected] world';

// First mask emails
text = RegexTransformer.transformations.maskEmails(text);
// 'hello [EMAIL] world'

// Then convert to title case
text = TextCaseConverter.convert(text, 'title');
// 'Hello [EMAIL] World'

Browser Support

This library works in all modern browsers and Node.js environments. It's written in TypeScript and compiled to ES5 for maximum compatibility.

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Run the test suite: npm test
6. Submit a pull request

License

MIT License - see LICENSE file for details.

Changelog

1.0.0

• Initial release
• Support for 9 case types
• Regex transformation capabilities
• TypeScript support
• Comprehensive test suite