Lower Case First

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

> Transform text by making the first character lowercase while preserving the rest.

🚀 Features

- Lightweight - Only ~200B minified + gzipped
- Type-safe - Full TypeScript support with comprehensive type definitions
- Zero dependencies - No external dependencies
- Tree-shakeable - ES modules support
- Universal - Works in browsers, Node.js, and serverless environments
- Well-tested - Comprehensive test suite with edge cases

📦 Installation

``bash


npm

npm install text-lower-case-first

yarn

yarn add text-lower-case-first

pnpm

pnpm add text-lower-case-first

bun

bun add text-lower-case-first
`

🎯 Quick Start

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

console.log(lowerCaseFirst("Hello World")); // "hello World"
console.log(lowerCaseFirst("HELLO WORLD")); // "hELLO WORLD"
console.log(lowerCaseFirst("CamelCase")); // "camelCase"
`

📖 Usage

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

console.log(lowerCaseFirst("Hello")); // "hello"
`

$3

`javascript
const { lowerCaseFirst } = require("text-lower-case-first");

console.log(lowerCaseFirst("Hello")); // "hello"
`

$3

`typescript
import { lowerCaseFirst } from "text-lower-case-first";

const result: string = lowerCaseFirst("Hello World");
console.log(result); // "hello World"
`

🔄 Transformation Examples

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

// Simple cases
lowerCaseFirst("Hello"); // "hello"
lowerCaseFirst("hello"); // "hello"
lowerCaseFirst("HELLO"); // "hELLO"

// Multiple words
lowerCaseFirst("Hello World"); // "hello World"
lowerCaseFirst("HELLO WORLD"); // "hELLO WORLD"
lowerCaseFirst("hello world"); // "hello world"

// Programming cases
lowerCaseFirst("CamelCase"); // "camelCase"
lowerCaseFirst("PascalCase"); // "pascalCase"
lowerCaseFirst("Snake_case"); // "snake_case"
lowerCaseFirst("Kebab-case"); // "kebab-case"
`

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

// Empty and single character
lowerCaseFirst(""); // ""
lowerCaseFirst("A"); // "a"
lowerCaseFirst("a"); // "a"

// Numbers and symbols
lowerCaseFirst("123hello"); // "123hello"
lowerCaseFirst("@Hello"); // "@Hello"
lowerCaseFirst("Hello123"); // "hello123"

// Unicode characters
lowerCaseFirst("Ñice"); // "ñice"
lowerCaseFirst("Über"); // "über"
lowerCaseFirst("Café"); // "café"
`

🌍 Real-World Examples

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

// Convert PascalCase to camelCase
lowerCaseFirst("UserProfile"); // "userProfile"
lowerCaseFirst("DatabaseConnection"); // "databaseConnection"
lowerCaseFirst("ApiResponse"); // "apiResponse"
lowerCaseFirst("HttpClient"); // "httpClient"
`

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

function convertObjectKeys(obj) {
const converted = {};

for (const [key, value] of Object.entries(obj)) {
const newKey = lowerCaseFirst(key);
converted[newKey] =
typeof value === "object" && value !== null
? convertObjectKeys(value)
: value;
}

return converted;
}

const apiResponse = {
UserName: "john_doe",
EmailAddress: "john@example.com",
ProfileData: {
FirstName: "John",
LastName: "Doe",
PhoneNumber: "123-456-7890",
},
};

console.log(convertObjectKeys(apiResponse));
// {
// userName: "john_doe",
// emailAddress: "john@example.com",
// profileData: {
// firstName: "John",
// lastName: "Doe",
// phoneNumber: "123-456-7890"
// }
// }
`

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

function createGetter(propertyName) {
const methodName = get${propertyName};
return lowerCaseFirst(methodName);
}

function createSetter(propertyName) {
const methodName = set${propertyName};
return lowerCaseFirst(methodName);
}

console.log(createGetter("UserName")); // "getUserName"
console.log(createSetter("EmailAddress")); // "setEmailAddress"
console.log(createGetter("IsActive")); // "getIsActive"
`

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

function processFormFields(fields) {
const processed = {};

fields.forEach((field) => {
// Convert field names to camelCase
const fieldName = lowerCaseFirst(field.Name || field.name);
processed[fieldName] = {
value: field.Value || field.value || "",
required: field.Required || field.required || false,
type: field.Type || field.type || "text",
};
});

return processed;
}

const formFields = [
{ Name: "FirstName", Value: "John", Required: true, Type: "text" },
{ Name: "LastName", Value: "Doe", Required: true, Type: "text" },
{ Name: "EmailAddress", Value: "", Required: true, Type: "email" },
];

console.log(processFormFields(formFields));
// {
// firstName: { value: "John", required: true, type: "text" },
// lastName: { value: "Doe", required: true, type: "text" },
// emailAddress: { value: "", required: true, type: "email" }
// }
`

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

function normalizeApiResponse(response) {
if (Array.isArray(response)) {
return response.map(normalizeApiResponse);
}

if (typeof response === "object" && response !== null) {
const normalized = {};

for (const [key, value] of Object.entries(response)) {
const normalizedKey = lowerCaseFirst(key);
normalized[normalizedKey] = normalizeApiResponse(value);
}

return normalized;
}

return response;
}

const apiData = {
UserId: 123,
UserName: "john_doe",
ProfileInfo: {
FirstName: "John",
LastName: "Doe",
ContactDetails: {
EmailAddress: "john@example.com",
PhoneNumber: "123-456-7890",
},
},
Preferences: [
{ SettingName: "theme", SettingValue: "dark" },
{ SettingName: "language", SettingValue: "en" },
],
};

console.log(normalizeApiResponse(apiData));
// {
// userId: 123,
// userName: "john_doe",
// profileInfo: {
// firstName: "John",
// lastName: "Doe",
// contactDetails: {
// emailAddress: "john@example.com",
// phoneNumber: "123-456-7890"
// }
// },
// preferences: [
// { settingName: "theme", settingValue: "dark" },
// { settingName: "language", settingValue: "en" }
// ]
// }
`

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

class CodeGenerator {
generateProperty(name, type = "string") {
const propertyName = lowerCaseFirst(name);
return private ${propertyName}: ${type};;
}

generateGetter(name, type = "string") {
const propertyName = lowerCaseFirst(name);
const methodName = get${name};
return public ${lowerCaseFirst(methodName)}(): ${type} {
return this.${propertyName};
};
}

generateSetter(name, type = "string") {
const propertyName = lowerCaseFirst(name);
const methodName = set${name};
const paramName = lowerCaseFirst(name);
return public ${lowerCaseFirst(methodName)}(${paramName}: ${type}): void {
this.${propertyName} = ${paramName};
};
}
}

const generator = new CodeGenerator();
console.log(generator.generateProperty("UserName"));
// "private userName: string;"

console.log(generator.generateGetter("UserName"));
// "public getUserName(): string {
// return this.userName;
// }"
`

$3

`javascript
import { lowerCaseFirst } from "text-lower-case-first";

function processConfiguration(config) {
const processed = {};

for (const [section, settings] of Object.entries(config)) {
const sectionName = lowerCaseFirst(section);
processed[sectionName] = {};

for (const [key, value] of Object.entries(settings)) {
const settingName = lowerCaseFirst(key);
processed[sectionName][settingName] = value;
}
}

return processed;
}

const appConfig = {
DatabaseSettings: {
ConnectionString: "localhost:5432",
MaxConnections: 100,
TimeoutSeconds: 30,
},
ApiSettings: {
BaseUrl: "https://api.example.com",
ApiKey: "secret-key",
RateLimitPerMinute: 1000,
},
};

console.log(processConfiguration(appConfig));
// {
// databaseSettings: {
// connectionString: "localhost:5432",
// maxConnections: 100,
// timeoutSeconds: 30
// },
// apiSettings: {
// baseUrl: "https://api.example.com",
// apiKey: "secret-key",
// rateLimitPerMinute: 1000
// }
// }
`

📖 API Reference

$3

Makes the first character of a string lowercase while preserving the rest.

#### Parameters

- input (string): The string to transform

#### Returns

- string: The string with the first character in lowercase

📊 Bundle Size

This package is optimized for minimal bundle size:

- Minified: ~200B
- Gzipped: ~150B
- Tree-shakeable: Yes
- Side effects: None

🌍 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

Type checking

pnpm typecheck

Linting

pnpm lint
`

🔗 Related Packages

- text-camel-case - Convert to camelCase
- text-capital-case - Convert to Capital Case
- text-constant-case - Convert to CONSTANT_CASE
- text-dot-case - Convert to dot.case
- text-header-case - Convert to Header-Case
- text-case - All case transformations in one package

📜 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
- 📖 Documentation: Full Documentation

---

Made with ❤️ by Dmitry Selikhov

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