后台表格导出excel

1、传入导出条件，调用后端接口，获取到导出数据，以及文件名称和文件路径。
2、调用以下方法，传入上述接口得到的数据以及文件名称。

 downloadXlsx(res, filename) {
      if ("download" in document.createElement("a")) {
        // 非IE下载
        const elink = document.createElement("a");
        elink.download = filename;
        elink.style.display = "none";
        //文件地址
        elink.href = res.file.url;
        document.body.appendChild(elink);
        elink.click();
        URL.revokeObjectURL(elink.href); // 释放URL 对象
        document.body.removeChild(elink);
      } else {
        // IE10+下载
        navigator.msSaveBlob(res, filename);
      }
    }

导出pdf的方法

通过canvas实现导出pdf；

export function exportPdf(
  dom,
  name,
  backgroundColor = "#f6f6f6",
  scale = 3.15
) {
  // window.getCanvas() //把svg的图表转成canvas
  return html2canvas(dom, {
    backgroundColor,
    width: dom.offsetWidth,
    height: dom.offsetHeight + 200,
    scale,
    useCORS: true
  }).then(function(canvas) {
    let width = canvas.style && canvas.style.width,
      height = canvas.style && canvas.style.height;
    let contentWidth = width.replace(/px/, "");
    let contentHeight = height.replace(/px/, "");
    let context = canvas.getContext("2d");
    context.webkitImageSmoothingEnabled = false;
    context.mozImageSmoothingEnabled = false;
    context.msImageSmoothingEnabled = false;
    context.imageSmoothingEnabled = false;
    let imageData = context.getImageData(0, 0, contentWidth, contentHeight);
    // 下面处理防止canvas转成img时 出现黑色背景，现在更改为白色背景
    for (let i = 0; i < imageData.data.length; i += 4) {
      // 当该像素是透明的，则设置成白色
      if (imageData.data[i + 3] === 0) {
        imageData.data[i] = 246;
        imageData.data[i + 1] = 246;
        imageData.data[i + 2] = 246;
        imageData.data[i + 3] = 246;
      }
    }
    context.putImageData(imageData, 0, 0);
    // 以上将html转成canvas完成,下面将canvas转成图片,由图片生成pdf
    var imgData = canvas.toDataURL("image/jpeg", 1.0); // 返回图片dataURL，参数：图片格式和清晰度(0-1)
    let img = new Image();
    img.src = imgData;
    img.onload = function() {
      let doc;
      if (contentWidth > contentHeight) {
        doc = new JsPDF("l", "pt", [contentWidth, contentHeight]);
      } else {
        doc = new JsPDF("p", "pt", [contentWidth, contentHeight]);
      }
      doc.addImage(imgData, "jpeg", 0, 0, contentWidth, contentHeight);
      doc.save((name || new Date().getTime()) + ".pdf");
    };
  });
}

导出img

细节方面，根据需要自己调整，我就不仔细说了。

export function exportImg(dom, name) {
  html2canvas(dom, {
    backgroundColor: "#fff",
    width: dom.offsetWidth,
    height: dom.offsetHeight + 10,
    scale: 3.125,
    useCORS: true
  }).then(function(image) {
    if (image.msToBlob) {
      navigator.msSaveBlob(image.msToBlob(), `${name || Date.now()}.png`);
    } else {
      let url = image.toDataURL("image/png", 1.0);
      let $a = document.createElement("a");
      let type = "png";
      $a.href = url;
      $a.target = "_blank";
      $a.download = name || "未命名" + "." + type;
      document.body.appendChild($a);
      $a.click();
      document.body.removeChild($a);
    }
  });
}