/**
 * Checks if a value is included in an array or a single value.
 *
 * @param val - The value to be checked.
 * @param keywords - An array or a single value for validation.
 * @returns `true` if the value is included, otherwise `false`.
 *
 * @example
 * includes([1, 2, 3], 2); // true
 * includes([1, 2, 3], 4); // false
 *
 * includes([1, 2, 3], 2); // true
 * includes([1, 2, 3], 4); // false
 *
 * includes({ name: "John", age: 23 }, { name: "John", age: 23 }); // true
 * includes({ name: "John", age: 23 }, { name: "John", age: 24 }); // false
 *
 * includes([1, 2, 3], [1, 2, 3]); // true
 * includes([1, 2, 3], [1, 2, 3, [4]]); // false
 * includes([1, 2, 3, [4]], [1, 2, 3, [4]]); // true
 *
 */
export declare function includes<T>(keywords: T, val: unknown): val is T;
export declare function includes<T>(keywords: T[], val: unknown): val is T;