javascript - 函数表达式是否假定词法封闭函数上下文的 this ？

Question

我对此很有信心function declarations does not has lexical context，arrow function it does have但我很困惑，如果function expression does？

根据我读到的内容，它没有，但在following example两种情况下都可以正常工作（使用函数表达式和箭头函数），所以在我看来它has lexical context。在我理解之后arrow function，它就是short syntax of the function expression这样same capacities。我错了吗？

查看未注释的代码：

// Delete users for ADMIN with GET 
        document.addEventListener("click", function (e) {

            if (e.target.classList.contains("btnDeleteUser")) {
                /// get users based on id
                sUserId = e.target.getAttribute("data-userId");
                //console.log(sUserId);
                /*getAjax("api_delete_user.php?id=" + sUserId, function(ajUserDataFromServer) {
                deleteUser(e, ajUserDataFromServer);*/
                /*getAjax("api_delete_user.php?id=" + sUserId, (ajUserDataFromServer) => {
                    deleteUser(e, ajUserDataFromServer); 
                    })*/
                getAjax("api_delete_user.php?id=" + sUserId, deleteUser.bind(this, e));

            }
        });