komoji ✨

the tiny case transformer

Effortlessly transform strings between naming conventions

Why komoji?

Named after the Japanese word 小文字 (komoji, "lowercase letters"), komoji is your friendly companion for working with naming conventions. It's tiny, focused, and does one thing exceptionally well: transforming strings between different cases with zero dependencies.

Perfect for:

• 🔄 Converting API responses to JavaScript conventions
• 🎨 Generating code from schemas and templates
• 🛠️ Building developer tools and CLI utilities
• 📦 Processing configuration files across formats

Install

npm install komoji

Usage

Transform to PascalCase

import { toPascalCase } from 'komoji';

toPascalCase('hello-world');      // HelloWorld
toPascalCase('user_name');        // UserName
toPascalCase('api response');     // ApiResponse
toPascalCase('my-component_v2');  // MyComponentV2

Transform to camelCase

import { toCamelCase } from 'komoji';

toCamelCase('hello-world');       // helloWorld
toCamelCase('user_name');         // userName
toCamelCase('api-response-data'); // apiResponseData

// Strip leading non-alphabetic characters
toCamelCase('__private_field', true);  // privateField
toCamelCase('123-invalid', true);      // invalid

Transform to snake_case

import { toSnakeCase } from 'komoji';

toSnakeCase('helloWorld');        // hello_world
toSnakeCase('UserName');          // user_name
toSnakeCase('api-response-data'); // api_response_data
toSnakeCase('myComponentV2');     // my_component_v2
toSnakeCase('HTTPSConnection');   // https_connection

Transform to kebab-case

import { toKebabCase } from 'komoji';

toKebabCase('helloWorld');        // hello-world
toKebabCase('UserName');          // user-name
toKebabCase('api_response_data'); // api-response-data
toKebabCase('myComponentV2');     // my-component-v2
toKebabCase('HTTPSConnection');   // https-connection

Transform to CONSTANT_CASE

import { toConstantCase } from 'komoji';

toConstantCase('helloWorld');        // HELLO_WORLD
toConstantCase('UserName');          // USER_NAME
toConstantCase('api-response-data'); // API_RESPONSE_DATA
toConstantCase('myComponentV2');     // MY_COMPONENT_V2
toConstantCase('HTTPSConnection');   // HTTPS_CONNECTION

Validate Identifiers

import { isValidIdentifier, isValidIdentifierCamelized } from 'komoji';

// Check if string is a valid JavaScript identifier
isValidIdentifier('myVar');        // true
isValidIdentifier('my-var');       // false
isValidIdentifier('123abc');       // false
isValidIdentifier('_private');     // true

// Check if string can be camelized into valid identifier
isValidIdentifierCamelized('my-var');   // true (can become myVar)
isValidIdentifierCamelized('valid_id'); // true
isValidIdentifierCamelized('-invalid'); // false (starts with hyphen)

API

Case Transformation Functions

toPascalCase(str: string): string

Converts a string to PascalCase by capitalizing the first letter of each word and removing separators.

Supported separators: hyphens (-), underscores (_), spaces ( )

toCamelCase(key: string, stripLeadingNonAlphabetChars?: boolean): string

Converts a string to camelCase with an optional flag to strip leading non-alphabetic characters.

Parameters:

• key - The string to transform
• stripLeadingNonAlphabetChars - Remove leading non-alphabetic characters (default: false)

toSnakeCase(str: string): string

Converts a string to snake_case. Handles camelCase, PascalCase, kebab-case, and space-separated strings. Properly inserts underscores between words and before numbers.

toKebabCase(str: string): string

Converts a string to kebab-case. Handles camelCase, PascalCase, snake_case, and space-separated strings. Properly inserts hyphens between words and before numbers.

toConstantCase(str: string): string

Converts a string to CONSTANT_CASE (also known as SCREAMING_SNAKE_CASE). Perfect for environment variables and constants. Handles all common case formats and properly separates words and numbers.

Validation Functions

isValidIdentifier(key: string): boolean

Checks if a string is a valid JavaScript identifier (follows standard naming rules).

isValidIdentifierCamelized(key: string): boolean

Checks if a string can be transformed into a valid JavaScript identifier (allows internal hyphens that will be removed during camelization).

Design Philosophy

komoji embraces simplicity:

• 🎯 Zero dependencies
• 🪶 Tiny footprint
• 🚀 Fast and predictable
• 💎 Pure functions
• 📖 Clear, focused API

Development

Setup

1. Clone the repository:

git clone https://github.com/constructive-io/dev-utils.git

2. Install dependencies:

cd dev-utils
pnpm install
pnpm build

3. Test the package of interest:

cd packages/<packagename>
pnpm test:watch

Credits

🛠 Built by the Constructive team — creators of modular Postgres tooling for secure, composable backends. If you like our work, contribute on GitHub.

Disclaimer

AS DESCRIBED IN THE LICENSES, THE SOFTWARE IS PROVIDED "AS IS", AT YOUR OWN RISK, AND WITHOUT WARRANTIES OF ANY KIND.

No developer or entity involved in creating this software will be liable for any claims or damages whatsoever associated with your use, inability to use, or your interaction with other users of the code, including any direct, indirect, incidental, special, exemplary, punitive or consequential damages, or loss of profits, cryptocurrencies, tokens, or anything else of value.