/**
 * Check if the value is a plain object
 *
 * 校验是否是一个普通对象
 *
 * @example
 * ```js
 * import { isPlainObject } from 'is-what-type';
 *
 * isPlainObject({}); // true
 * isPlainObject({ key: 'value' }); // true
 * isPlainObject([]); // false
 * isPlainObject(null); // false
 * isPlainObject(undefined); // false
 * isPlainObject(function() {}); // false
 * isPlainObject(new Date()); // false
 * isPlainObject(new (class {})()); // false
 *
 * function Fn() {}
 * isPlainObject(new Fn()); // false
 * ```
 *
 * @param value The value to check
 * @returns `true` if the value is a plain object, else `false`
 */
export declare function isPlainObject<T = object>(value: unknown): value is T;