//res.data   接口获取到的数据
　　　　　　if (res.data.length == 1) {//单个下载图片
            let data = `${this.$moment(new Date()).format('YYYY-MM-DD')}`  //下载文件名字以时间命名
            var image = new Image();
            // 解决跨域 Canvas 污染问题
            image.setAttribute("crossOrigin", "anonymous");
            image.onload = function () {
              var canvas = document.createElement("canvas");
              canvas.width = image.width;
              canvas.height = image.height;
              var context = canvas.getContext("2d");
              context.drawImage(image, 0, 0, image.width, image.height);
              var url = canvas.toDataURL("image/png"); //得到图片的base64编码数据
              var a = document.createElement("a"); // 生成一个a元素
              var event = new MouseEvent("click"); // 创建一个单击事件
              a.download = data + '_1' || "photo"; // 设置图片名称
              a.href = url; // 将生成的URL设置为a.href属性
              a.dispatchEvent(event); // 触发a的单击事件
            };
　　　　　　　//单个图片下载路径
            image.src = res.data[0].filePath;
          } else {//多个文件夹里面包含图片
            let blogTitle = "电子发票"; //文件夹名
            let zip = new JSZip();
            let imgs = zip.folder(blogTitle);
            let baseList = [];
　　　　　　　//下载的数据及格式整理
            let arr = res.data;
            let exportImg = arr.map((item, index) => {//数组对象
              return {
                name: `${this.$moment(new Date()).format('YYYY-MM-DD')}_${index + 1}`, //文件名字
                images: item.filePath,//文件链接
              };
            })
            this.imgLoading = false;
            for (let i = 0; i < exportImg.length; i++) {
              let image = new Image();
              // 解决跨域 Canvas 污染问题
              image.setAttribute("crossOrigin", "anonymous");
              image.onload = function () {
                let canvas = document.createElement("canvas");
                canvas.width = image.width;
                canvas.height = image.height;
                let context = canvas.getContext("2d");
                context.drawImage(image, 0, 0, image.width, image.height);
                let url = canvas.toDataURL(); // 得到图片的base64编码数据
                canvas.toDataURL("image/png");
                baseList.push(url.substring(22)); // 去掉base64编码前的 data:image/png;base64,
                if (baseList.length === exportImg.length && baseList.length > 0) {
                  for (let k = 0; k < baseList.length; k++) {
                    imgs.file(exportImg[k].name + ".png", baseList[k], {
                      base64: true,
                    });
                  }
                  zip.generateAsync({ type: "blob" }).then(function (content) {
                    FileSaver.saveAs(content, blogTitle + ".zip");  // see FileSaver.js
                  });
                }
              };
              image.src = exportImg[i].images;
            }
          }