/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/
 */
/**
 * @param defaults function that returns the defaults of the record. This is done as a function rather than a literal so
 * that the defaults are calculated lazily, i.e. after everything has been declared.
 * @returns a function to create a new {T} with a partial that requires at least the missing keys to be present.
 */
export const uniffiCreateRecord = <T, D extends Partial<T>>(
  defaults: () => D,
) => {
  // OptionalKeys extracts keys declared with `?:` in T
  type OptionalKeys<O> = {
    [K in keyof O]-?: undefined extends O[K] ? K : never;
  }[keyof O];
  type MissingKeys = Omit<T, keyof D | OptionalKeys<T>>;
  return (partial: Partial<T> & Required<MissingKeys>): T =>
    Object.freeze({ ...defaults(), ...partial } as T);
};