es6 如何获得实例化对象的方法？

Question

例如

class NumPicker {
    constructor(current = 1, min = 1, max = 10, cutCallback = () => {}, addCallback = () => {}, alwaysCallback = () => {}) {
        this.numPicker = {};
        this.numPicker.current = current;
        this.numPicker.minNum = min;
        this.numPicker.maxNum = max;
    }

    addNum() {
        let that = this;
        if (that.num_picker.current <= that.num_picker.minNum) {
            return;
        } else {
            that.num_picker.current--;
            alwaysCallback(that.num_picker.current);
            cutCallback(that.num_picker.current);
        }
    }
    cutNum() {
        let that = this;
        if (that.num_picker.current <= that.num_picker.maxNum) {
            that.num_picker.current++;
            addCallback(that.num_picker.current);
            alwaysCallback(that.num_picker.current);
        } else {
            return;
        }
    }
};

然后我let p = new NumPicker(); 怎样获得p的方法？

我用

    for(let key in p.__proto__) {
        console.log(key)
    }

并不能得到啊

Answer 1

Object.getOwnPropertyNames(Object.getPrototypeOf(p))

Answer 2

es6 内部定义的方法都是不可枚举的，你如果要遍历就NumPicker.prototype.addNum=()=>{}