/**
 * Frequently used types and type helpers for TypeScript.
 * @module
 */
/**
 * Make selected properties in T optional.
 * @typeParam T - The type to make partial.
 * @typeParam K - The keys of T to make optional.
 */
export type PartialBy<T, K extends keyof T> = Omit<T, K> & Partial<Pick<T, K>>;
/**
 * Get the return type of the toJSON method of an object.
 * @typeParam T - The object type.
 */
export type SaveData<T extends {
    toJSON: () => unknown;
}> = ReturnType<T['toJSON']>;
export type ArrayKeys<T> = {
    [K in keyof T]: T[K] extends unknown[] | undefined ? K : never;
}[keyof T];
export type StringKeys<T> = {
    [K in keyof T]: T[K] extends string | undefined ? K : never;
}[keyof T];
export type StringArrayKeys<T> = {
    [K in keyof T]: T[K] extends string[] | undefined ? K : never;
}[keyof T];