/**
 * 栈数组
 */
export declare class Stack {
    items: WeakMap<object, any>;
    constructor(options?: {
        items?: WeakMap<any, any>;
    });
    /**
     * 入栈
     * @ param element
     */
    push(element: any): void;
    /**
     * 出栈
     */
    pop(): any;
    /**
     * 栈顶值
     */
    peek(): any;
    /**
     * 栈是否为空
     */
    isEmpty(): boolean;
    /**
     * 栈长度
     */
    size(): number;
    /**
     * 清空栈
     */
    clear(): void;
}