ts-case-change converts object keys between camelCase and snake_case while preserving Typescript type information, code completion, and type validation. See tests for detailed conversion tests.

Features

• Convert objects from snake_case to camelCase
• Convert objects from camelCase to snake_case
• Convert objects to PascalCase
• Preserve prefix characters like _ and $ during conversion
• Maintain full TypeScript type safety throughout conversion
• Handle nested objects and arrays
• Special handling for Date objects and Uint8Array/Buffer

Installation

# Recommended
pnpm add ts-case-change

# Alternative package managers
npm install ts-case-change
yarn add ts-case-change

Usage

import { objectToCamel, objectToSnake, objectToPascal, objectToCamelPrefix } from 'ts-case-change';

// Convert from snake_case to camelCase
const camel = objectToCamel({
  hello_world: 'helloWorld',
  a_number: 5,
  an_array: [1, 2, 4],
  null_object: null,
  undef_object: undefined,
  an_array_of_objects: [{ a_b: 'ab', a_c: 'ac' }],
  an_object: {
    a_1: 'a1',
    a_2: 'a2',
  },
});

type CheckCamel = typeof camel.anArrayOfObjects[0]['aB']; // -> 'string'
const camelValue: CheckCamel = camel.anArrayOfObjects[0]['aB']; // -> valid
console.log(camel.anArrayOfObjects[0].aB); // -> 'ab'

// Convert from camelCase to snake_case
const snake = objectToSnake({
  helloWorld: 'helloWorld',
  aNumber: 5,
  anArray: [1, 2, 4],
  nullObject: null,
  undefObject: undefined,
  anArrayOfObjects: [{ aB: 'ab', aC: 'ac' }],
  anObject: {
    A1: 'a_1',
    A2: 'a_2',
  },
});

type CheckSnake = typeof snake.an_array_of_objects[0]['a_b']; // -> 'string'
const snakeValue: CheckSnake = snake.an_array_of_objects[0]['a_b']; // -> valid
console.log(snake.an_array_of_objects[0].a_b); // -> 'ab'

// Convert to camelCase while preserving prefixes like _ and $
const prefixCamel = objectToCamelPrefix({
  _hello_world: 'helloWorld',
  $a_number: 5,
  an_array_with_$prefix: ['$value1', '$value2'],
  _nested_object: {
    _inner_value: 'innerValue',
    $dollar_prefix: 'dollarPrefix'
  }
});

// Prefixes are preserved
console.log(prefixCamel._helloWorld); // -> 'helloWorld'
console.log(prefixCamel.$aNumber); // -> 5
console.log(prefixCamel.anArrayWith$prefix); // -> ['$value1', '$value2']
console.log(prefixCamel._nestedObject._innerValue); // -> 'innerValue'
console.log(prefixCamel._nestedObject.$dollarPrefix); // -> 'dollarPrefix'

Development

Building the project

pnpm build

Running tests

pnpm test
pnpm test:watch  # Run tests in watch mode
pnpm test:coverage  # Run tests with coverage report

Code quality

pnpm lint  # Run ESLint
pnpm format  # Format code with Prettier

Documentation

See tests for detailed examples.

Acknowledgments

This project is a fork of ts-case-convert by Ross Williams.

📝 License

Copyright © 2021 Ross Williams (original author) Copyright © 2025 Jordan Burke This project is Apache-2.0 licensed.