es-toolkit/dist/types/ToConstantCaseKeys.d.ts

A state-of-the-art, high-performance JavaScript utility library with a small bundle size and strong type annotations.

import { NonPlainObject } from "../_internal/NonPlainObject.js";

//#region src/types/ToConstantCaseKeys.d.ts
type ConstantCase<S extends string> = S extends Lowercase<S> ? Uppercase<S> : S extends `${infer P1}${infer P2}` ? P2 extends Uncapitalize<P2> ? `${Uppercase<P1>}${ConstantCase<P2>}` : `${Uppercase<P1>}_${ConstantCase<Uncapitalize<P2>>}` : Uppercase<S>;
/**
 * Converts the keys of `T` to CONSTANT_CASE recursively.
 *
 * This is the return type of the `toConstantCaseKeys` function. Recurses into
 * plain objects and arrays; built-in objects like `Date`, `Map`, and functions
 * pass through unchanged.
 *
 * @template T - The type whose keys are converted.
 *
 * @example
 * type Response = { userId: number; firstName: string };
 * type Converted = ToConstantCaseKeys<Response>;
 * // => { USER_ID: number; FIRST_NAME: string }
 */
type ToConstantCaseKeys<T> = T extends NonPlainObject ? T : T extends any[] ? Array<ToConstantCaseKeys<T[number]>> : T extends Record<string, any> ? { [K in keyof T as ConstantCase<string & K>]: ToConstantCaseKeys<T[K]> } : T;
//#endregion
export { ToConstantCaseKeys };