删除最后一页的最后一条数据，没回到前一页

// 更新当前页码
            let totalPage = Math.ceil((this.totalNum - 1)/this.pageSize);
            let currentPage = this.currentPage > totalPage ? totalPage : this.currentPage;
            this.currentPage = this.currentPage < 1 ? 1 : currentPage;

参考博客：http://www.javashuo.com/article/p-aypwjyfo-nn.html