js Base64 文件上传

// base64 转 二进制流(blob)
    dataURLtoBlob(dataurl) {
      var arr = dataurl.split(","),
        mime = arr[0].match(/:(.*?);/)[1],
        bstr = atob(arr[1]),
        n = bstr.length,
        u8arr = new Uint8Array(n);
      while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
      }
      return new Blob([u8arr], {
        type: mime,
      });
    }


let file = dataURLtoFile(base64, name);//实例化FormData
var formdata = new FormData();
//将文件信息存入formdata，键名为file
ll formdata会将文件信息序列化为ajax可识别的数据类型
formdata.append("file", file);
$.ajax({
type: "post",
url: uploadUrl,
data: formdata, ll formdata直接赋值给data
processData: false,//formdata已将数据序列化，无需在处理
contentType: false,//formdata无需设置请求头
success: function (res){
resolve(res.data)}
});