base64转file

方法一： 

不兼容ie11

export function dataURLtoFile(dataurl, filename) {
  let 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 File([u8arr], filename, {type:mime});
}

const file = dataURLtoFile(base64, '图片名称');

方法二:

兼容ie11

export function dataURLtoBlob(dataurl) {
  let 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 });
}

export function blobToFile(theBlob, fileName) {
  theBlob.lastModifiedDate = new Date();
  theBlob.name = fileName;
  return theBlob;
}

export function dataURLtoFile(dataurl, filename) {
  const blob = dataURLtoBlob(dataurl);
  const file = blobToFile(blob, filename);
  return file
}

const file = dataURLtoFile(base64, '图片名称');