/* 栈实现 */
const Stack = (() => {
    // 闭包使得item为私有变量，避免外部调用（ES6无私有变量）
    let item = new WeakMap();
    // 模拟实现栈 Stack
    class Stack {
        constructor() {
            item.set(this, []);
        }

        push(v) {
            let rem = item.get(this);
            rem.push(v);
        }

        pop() {
            let rem = item.get(this);
            return rem.pop();
        }

        peek() {
            let rem = item.get(this);
            return rem[rem.length];
        }

        clear() {
            item.set(this, []);
        }

        isEmpty() {
            let rem = item.get(this);
            return rem.length === 0;
        }
    }
    return Stack;
})();


// test
// 二进制数转换，使用栈来解决
function devideBy2(decNumber) {
    let remStack = new Stack();
    let rem;
    let binaryString = '';

    while (decNumber > 0) {
        rem = Math.floor(decNumber % 2);
        remStack.push(rem);
        decNumber = Math.floor(decNumber / 2);
    }

    while (!remStack.isEmpty()) {
        binaryString += remStack.pop().toString();
    }

    return binaryString;
}