关于javascript:JS-文件base64FileBlobArrayBuffer互转

二进制互转

1. file 对象转 base64

 let reader = new FileReader();
 reader.readAsDataURL(file[0])
 console.log(reader)

2. base64 转成 blob 上传

function dataURItoBlob(dataURI) {var byteString = atob(dataURI.split(',')[1]);  
    var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];  
    var ab = new ArrayBuffer(byteString.length);  
    var ia = new Uint8Array(ab);  
    for (var i = 0; i < byteString.length; i++) {ia[i] = byteString.charCodeAt(i);  
    }  
    return new Blob([ab], {type: mimeString});  
}

3. blob 转成 ArrayBuffer

let blob = new Blob([1,2,3,4])
let reader = new FileReader();
reader.onload = function(result) {console.log(result);
}
reader.readAsArrayBuffer(blob);

4. buffer 转成 blob

let blob = new Blob([buffer])

5. base64 转 file

const base64ConvertFile = function (urlData, filename) { // 64 转 file
  if (typeof urlData != 'string') {this.$toast("urlData 不是字符串")
    return;
  }
  var arr = urlData.split(',')
  var type = arr[0].match(/:(.*?);/)[1]
  var fileExt = type.split('/')[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.' + fileExt, {type: type});
}