base64转File

1. 先转blob，再转File（兼容好）

//将base64转换为blob
  dataURLtoBlob: function(dataurl) { 
      var  arr = dataurl.split(',')
      var  mime = arr[0].match(/:(.*?);/)[1]
      var  bstr = atob(arr[1])
      var  n = bstr.length
      var  u8arr = new Uint8Array(n)
      while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
      }
      return new Blob([u8arr], { type: mime });
  },
  //将blob转换为file
  blobToFile: function(theBlob, fileName){
      theBlob.lastModifiedDate = new Date();
      theBlob.name = fileName;
      return theBlob;
  },
  //调用
  var blob = dataURLtoBlob(base64Data);
  var file = blobToFile(blob, imgName);

2. 直接转File（兼容差）

//将base64转换为文件
  dataURLtoFile: function(dataurl, filename) { 
      var arr = dataurl.split(',')
      var mime = arr[0].match(/:(.*?);/)[1]
      var bstr = atob(arr[1])
      var n = bstr.length
      var u8arr = new Uint8Array(n)
      while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
      }
      return new File([u8arr], filename, { type: mime });
  }
  //调用
  var file = dataURLtoFile(base64Data, imgName);

出处：https://lolosong.com/post/base64tofile.html