Text Case

[![NPM version][npm-image]][npm-url]
[![NPM downloads][downloads-image]][downloads-url]
[![Bundle size][bundlephobia-image]][bundlephobia-url]

> The ultimate text case transformation library for JavaScript and TypeScript. Convert text between camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, Title Case, Sentence case, dot.case, path/case, Header-Case, and many more formats with comprehensive TypeScript support.

🚀 Features

- 21 case transformation functions covering all common text formatting needs
- Type-safe with comprehensive TypeScript definitions
- Zero dependencies - lightweight and fast
- Tree-shakeable - import only what you need
- Universal - works in browsers, Node.js, and serverless environments
- Comprehensive testing - 100% test coverage with extensive edge cases
- Professional documentation - detailed examples and API references
- Modern tooling - ES modules, CommonJS, and UMD support

📦 Installation

``bash


npm

npm install text-case

yarn

yarn add text-case

pnpm

pnpm add text-case

bun

bun add text-case
`

🎯 Quick Start

`javascript
import {
camelCase, // userProfileData
pascalCase, // UserProfileData
kebabCase, // user-profile-data
snakeCase, // user_profile_data
titleCase, // User Profile Data
sentenceCase, // User profile data
constantCase, // USER_PROFILE_DATA
dotCase, // user.profile.data
pathCase, // user/profile/data
headerCase, // User-Profile-Data
capitalCase, // User Profile Data
noCase, // user profile data
paramCase, // user-profile-data (alias for kebab-case)
upperCase, // USER PROFILE DATA
lowerCase, // user profile data
upperCaseFirst, // User profile data
lowerCaseFirst, // user Profile Data
swapCase, // uSER pROFILE dATA
isUpperCase, // Boolean check
isLowerCase, // Boolean check
} from "text-case";

// Transform any text format
const input = "user_profile_data";

console.log(camelCase(input)); // "userProfileData"
console.log(pascalCase(input)); // "UserProfileData"
console.log(kebabCase(input)); // "user-profile-data"
console.log(titleCase(input)); // "User Profile Data"
`

📚 Available Functions

$3

| Function | Output Example | Description |
| ---------------- | ------------------- | -------------------------------------------------- |
| camelCase() | userProfileData | First word lowercase, subsequent words capitalized |
| pascalCase() | UserProfileData | All words capitalized, no separators |
| snakeCase() | user_profile_data | Lowercase words separated by underscores |
| kebabCase() | user-profile-data | Lowercase words separated by hyphens |
| titleCase() | User Profile Data | All words capitalized, separated by spaces |
| sentenceCase() | User profile data | First word capitalized, rest lowercase |

$3

| Function | Output Example | Description |
| ---------------- | ------------------- | -------------------------------------------- |
| constantCase() | USER_PROFILE_DATA | Uppercase words separated by underscores |
| dotCase() | user.profile.data | Lowercase words separated by dots |
| pathCase() | user/profile/data | Lowercase words separated by forward slashes |
| headerCase() | User-Profile-Data | Capitalized words separated by hyphens |
| capitalCase() | User Profile Data | All words capitalized, separated by spaces |
| noCase() | user profile data | Lowercase words separated by spaces |
| paramCase() | user-profile-data | Alias for kebab-case |

$3

| Function | Output Example | Description |
| ------------------ | ------------------- | --------------------------- |
| upperCase() | USER PROFILE DATA | All characters uppercase |
| lowerCase() | user profile data | All characters lowercase |
| upperCaseFirst() | User profile data | First character uppercase |
| lowerCaseFirst() | user Profile Data | First character lowercase |
| swapCase() | uSER pROFILE dATA | Swap case of all characters |

$3

| Function | Output Example | Description |
| --------------- | -------------- | ---------------------------- |
| isUpperCase() | true/false | Check if string is uppercase |
| isLowerCase() | true/false | Check if string is lowercase |

🛠️ Advanced Usage

$3

All transformation functions accept an optional second parameter for customization:

`javascript
import { camelCase, snakeCase } from "text-case";

// Custom word splitting
camelCase("XMLHttpRequest", {
splitRegexp: /([a-z])([A-Z])/g,
}); // "xmlHttpRequest"

// Custom character stripping
snakeCase("hello@world.com", {
stripRegexp: /[@.]/g,
}); // "hello_world_com"

// Custom transformations
camelCase("api-v2-endpoint", {
transform: (word, index) => {
if (word === "api") return "API";
if (word === "v2") return "V2";
return word;
},
}); // "APIV2Endpoint"
`

$3

Full TypeScript support with comprehensive type definitions:

`typescript
import { camelCase, Options } from "text-case";

// Type-safe options
const options: Options = {
splitRegexp: /([a-z])([A-Z])/g,
stripRegexp: /[^a-zA-Z0-9]/g,
transform: (word: string, index: number, words: string[]) =>
word.toLowerCase(),
};

// Type inference
const result: string = camelCase("hello-world", options);
`

$3

#### API Development

`javascript
import { camelCase, snakeCase, kebabCase } from "text-case";

// Convert database columns to JavaScript
const dbUser = {
first_name: "John",
last_name: "Doe",
email_address: "john@example.com",
};
const jsUser = Object.fromEntries(
Object.entries(dbUser).map(([key, value]) => [camelCase(key), value]),
);
// { firstName: "John", lastName: "Doe", emailAddress: "john@example.com" }

// Generate API endpoints
const createEndpoint = (resource, action) =>
/api/${kebabCase(resource)}/${kebabCase(action)};

createEndpoint("UserProfile", "GetById"); // "/api/user-profile/get-by-id"
`

#### React Development

`javascript
import { pascalCase, camelCase } from "text-case";

// Component generation
const createComponent = (name) =>
import React from 'react';

interface ${pascalCase(name)}Props {
${camelCase(name)}Data?: any;
}

export const ${pascalCase(name)}: React.FC<${pascalCase(name)}Props> = ({ ${camelCase(name)}Data }) => {
return

;
};
;

console.log(createComponent("user_profile_card"));
`

#### Configuration Management

`javascript
import { constantCase, camelCase } from "text-case";

// Environment variables to config object
const envToConfig = (envVars) => {
return Object.fromEntries(
Object.entries(envVars)
.filter(([key]) => key.startsWith("APP_"))
.map(([key, value]) => [camelCase(key.replace("APP_", "")), value]),
);
};

const env = {
APP_DATABASE_URL: "postgres://...",
APP_API_SECRET_KEY: "secret123",
APP_MAX_FILE_SIZE: "10MB",
};

const config = envToConfig(env);
// { databaseUrl: "postgres://...", apiSecretKey: "secret123", maxFileSize: "10MB" }
`

📖 API Reference

$3

`typescript
interface Options {
// RegExp to split input into words
splitRegexp?: RegExp;

// RegExp to strip unwanted characters
stripRegexp?: RegExp;

// Custom word transformation function
transform?: (word: string, index: number, words: string[]) => string;

// Custom split function (alternative to splitRegexp)
split?: (value: string) => string[];

// Delimiter between words (for spaced formats)
delimiter?: string;
}
`

$3

`javascript
// Split on camelCase and PascalCase boundaries
const camelSplit = { splitRegexp: /([a-z])([A-Z])/g };

// Preserve numbers as separate words
const numberSplit = { splitRegexp: /([a-zA-Z])(\d)/g };

// Strip special characters
const stripSpecial = { stripRegexp: /[^a-zA-Z0-9]/g };

// Custom acronym handling
const acronymTransform = {
transform: (word) => {
const acronyms = ["API", "URL", "HTTP", "JSON", "XML"];
return acronyms.includes(word.toUpperCase()) ? word.toUpperCase() : word;
},
};
`

📊 Bundle Size

This package is optimized for minimal bundle size:

- Minified: ~8KB (all functions)
- Gzipped: ~3KB (all functions)
- Tree-shakeable: Yes
- Side effects: None

For even smaller bundles, consider using individual packages:

`javascript
// ❌ Imports entire library (~8KB)
import { camelCase } from "text-case";

// ✅ Imports only camelCase (~450B)
import { camelCase } from "text-camel-case";
`

🌍 Browser Support

- Modern browsers: ES2015+ (Chrome 51+, Firefox 54+, Safari 10+)
- Node.js: 12+
- TypeScript: 4.0+
- Bundle formats: UMD, ESM, CommonJS

🧪 Testing

`bash


Run tests

pnpm test

Run tests in watch mode

pnpm test --watch

Run tests with coverage

pnpm test --coverage
`

🔗 Individual Packages

For optimal bundle size, you can install individual packages:

- text-camel-case - camelCase transformation
- text-pascal-case - PascalCase transformation
- text-snake-case - snake_case transformation
- text-kebab-case - kebab-case transformation
- text-title-case - Title Case transformation
- text-sentence-case - Sentence case transformation
- text-constant-case - CONSTANT_CASE transformation
- text-dot-case - dot.case transformation
- text-path-case - path/case transformation
- text-header-case - Header-Case transformation
- text-capital-case - Capital Case transformation
- text-no-case - no case transformation
- text-param-case - param-case transformation
- text-upper-case - UPPER CASE transformation
- text-lower-case - lower case transformation
- text-upper-case-first - Upper case first transformation
- text-lower-case-first - lower case first transformation
- text-swap-case - sWaP cAsE transformation
- text-is-upper-case - UPPER CASE validation
- text-is-lower-case - lower case validation

📜 License

MIT © Dmitry Selikhov

🤝 Contributing

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

🆘 Support

- 📧 Email: selikhov.dmitrey@gmail.com
- 🐛 Issues: GitHub Issues
- 💬 Discussions: GitHub Discussions

---

Made with ❤️ by Dmitry Selikhov

[npm-image]: https://img.shields.io/npm/v/text-case.svg?style=flat
[npm-url]: https://npmjs.org/package/text-case
[downloads-image]: https://img.shields.io/npm/dm/text-case.svg?style=flat
[downloads-url]: https://npmjs.org/package/text-case
[bundlephobia-image]: https://img.shields.io/bundlephobia/minzip/text-case.svg
[bundlephobia-url]: https://bundlephobia.com/result?p=text-case