base64与file格式图片转换

title: base64与file格式图片转换
date: 2019-03-26 15:14:44
tags: js

base64转file

function dataURLtoFile(dataurl, filename) {
  //将base64转换为文件
  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 File([u8arr], filename, {
    type: mime
  });
}
var file = dataURLtoFile(imgUrl, "img");

file转base64

base64转blob,blob转file

function 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 });
};
    //将blob转换为file
function blobToFile:(theBlob, fileName){
  theBlob.lastModifiedDate = new Date();
  theBlob.name = fileName;
  return theBlob;
};
//调用
var blob = dataURLtoBlob(base64Data);
var file = blobToFile(blob, imgName);