base64、File、Blob、ArrayBuffer 互转

file 对象转 base64

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

base64 转成 blob 上传

  1. function dataURItoBlob(dataURI) {
  2.   var byteString = atob(dataURI.split(',')[1]);
  3.   var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];
  4.   var ab = new ArrayBuffer(byteString.length);
  5.   var ia = new Uint8Array(ab);
  6.   for (var i = 0; i < byteString.length; i++) {
  7.     ia[i] = byteString.charCodeAt(i);
  8.   }
  9.   return new Blob([ab], { type: mimeString });
  10. }

blob 转成 ArrayBuffer

  1. let blob = new Blob([1,2,3,4])
  2. let reader = new FileReader();
  3. reader.onload = function(result) {
  4.     console.log(result);
  5. }
  6. reader.readAsArrayBuffer(blob);

buffer 转成 blob

  1. let blob = new Blob([buffer])

base64 转 file

  1. const base64ConvertFile = function (urlData, filename) { // 64转file
  2.   if (typeof urlData != 'string') {
  3.     this.$toast("urlData不是字符串")
  4.     return;
  5.   }
  6.   var arr = urlData.split(',')
  7.   var type = arr[0].match(/:(.*?);/)[1]
  8.   var fileExt = type.split('/')[1]
  9.   var bstr = atob(arr[1])
  10.   var n = bstr.length
  11.   var u8arr = new Uint8Array(n)
  12.   while (n--) {
  13.     u8arr[n] = bstr.charCodeAt(n);
  14.   }
  15.   return new File([u8arr], 'filename.' + fileExt, {
  16.     type: type
  17.   });
  18. }