Convert camel case object literal to snake case in TypeScript

converter.ts

type CamelToSnake<T extends string, P extends string = ""> = string extends T
  ? string
  : T extends `${infer C0}${infer R}`
  ? CamelToSnake<
      R,
      `${P}${C0 extends Lowercase<C0> ? "" : "_"}${Lowercase<C0>}`
    >
  : P;

type CamelKeysToSnake<T> = {
  [K in keyof T as CamelToSnake<Extract<K, string>>]: T[K];
};

/**
 * Convert object literal with camel case properties
 * to the same object with snake case properties.
 * @param input
 * @returns
 */
export const camelCaseObjectToSnakeCase = <T extends Record<string, any>>(
  input: T
): CamelKeysToSnake<T> => {
  return Object.keys(input).reduce((acc, cur) => {
    const key = cur.replace(
      /[A-Z]/g,
      (k) => `_${k.toLowerCase()}`
    ) as keyof CamelKeysToSnake<T>;
    acc[key] = input[cur];
    return acc;
  }, {} as CamelKeysToSnake<T>);
};