file、blob、base64相互转换

blob

blob转file

const blob = '.....'
const file = new File([blob], 'name.wav', {type: 'audio/wav'});

blob转base64

const blob = '.....'
const a = new FileReader();
a.readAsDataURL(blob);
a.onload = (e) => {
  const base64 = e.target.result
}

blob转blobUrl

const blob = '.....'
window.URL = window.URL || window.webkitURL;
const blobURL = window.URL.createObjectURL(blob);

file

file转blob

const file = '.....'
const a = new FileReader();
a.readAsDataURL(file);
a.onload = (e) => {
    const blob = new Blob([e.target.result], { type: file.type }) // 如果发现乱码检查一下type赋值的对不对
}

file转base64

const file = '.....'
const a = new FileReader();
a.readAsDataURL(file);
a.onload = (e) => {
    const base64 = e.target.result
}

file转buffer

const file = '.....'
const buffer = fileReader.readAsArrayBuffer(file)

file转binary(二进制格式)

const file = '.....'
const buffer = fileReader.readAsBinaryString(file)

file转file(用于修改file的只读属性name、type、lastModified)

const newFile = new File([file], 'newName.wav', {type: 'audio/wav', lastModified: Date.now()})

base64

base64转file

const arr = base64.split(',')
const type = arr[0].match(/:(.*?);/)[1]
const size = window.atob(arr[1])
let n = size.length
const u8arr = new Uint8Array(n)
while (n--) {
  u8arr[n] = size.charCodeAt(n)
}
const file = new File([u8arr], name, { type })

base64转blob

const arr = base64.split(',')
const type = arr[0].match(/:(.*?);/)[1]
const size = window.atob(arr[1])
let n = size.length
const u8arr = new Uint8Array(n)
while (n--) {
  u8arr[n] = size.charCodeAt(n)
}
const blob = new Blob([u8arr], { type })

base64操作

const arr = base64.split(',')
const type = arr[0].match(/:(.*?);/)[1] // image/jpeg
const size = window.atob(arr[1]).length
base加解密 -- 不支持中文
场景：由于一些网络通讯协议的限制,必须对原数据进行编码后才可发送，后端得到后再解码得到原数据，例如，发送某些含有 ASCII 码表中 0 到 31 之间的控制字符的数据。
base转码
const base64 = window.btoa('a')
base解码
const string = window.atob(base64)

转载自：(64条消息) （前端）file、blob、base64相互转换_由本的博客-CSDN博客_前端file转base64