base64文件处理

base64转换

• base64转图片
  

  1	data:${type};base64,+code

  type是文件类型，比如图片image/png,image/jpeg,pdf:application/pdf

• base64转为Blob对象
  

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  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 }); } let blob = dataURLtoBlob(data:${mimetype};base64,+image)`)

• blob转为File
  

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  function blobToFile(theBlob, fileName){ theBlob.lastModifiedDate = new Date(); theBlob.name = fileName; return theBlob; } var file = blobToFile(blob, imgName);

• base64转为File对象
  

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  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}); } let file = dataURLtoFile(data:${mimetype};base64,+image)`,'PDF.pdf')

• 转为url
  

  1	window.URL.createObjectURL(blob|file)

• 下载
  

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  let a=document.getElementById('download'); let blob=dataURLtoBlob(data:${image[0].mimetype};base64,+image[0].image); a.download = image[0].name+'.pdf'; a.href = window.URL.createObjectURL(blob)