This 指针指向问题和宏任务的执行顺序结合

普通函数内部，谁调用的函数，this 就指向谁

var User = {count:1,action: {getCount:function () {console.log('this',this)return this.count;}}};var getCount= User.action.getCount;setTimeout(() => {console.log('result 1', User.action.getCount());})console.log('result 2', getCount());//输出
'this', window
result 2 undefined
'this', {getCount: ?}
result 1 undefined