SOURCE

//利用闭包形成私有变量
let doaction = (function () {
    let switchbtn = document.querySelector("#switchbtn");
    let operate = document.querySelector("#operate");
    let switch1 = 0;
    return {
        init: function() {
            let _this = this;
            this.switchtxt(switch1);
            switchbtn.addEventListener("click", function() {
                switch1 = switch1 == 0 ? 1 : 0;
                _this.switchtxt(switch1);
            });
            operate.addEventListener("click", function() {
                _this.showmsg();
            });
        },
        switchtxt: function(txt) {
            document.querySelector("#switchtxt").innerHTML = txt;
        },
        showmsg: function() {
            document.querySelector("#msg").innerHTML = switch1;
        }
    };
})();

doaction.init();

<button id="switchbtn">切换状态，1变0，0变1</button> <span id="switchtxt"></span><br><br>
<button id="operate">执行函数，获取状态变量</button> <span id="msg"></span>