Base64与文件之间的互转

// 文件转base64
export const getBase64 = (file) => {
    
    
  return new Promise(function (resolve, reject) {
    
    
    let reader = new FileReader()
    let imgResult = ''
    reader.readAsDataURL(file)
    reader.onload = function () {
    
    
      imgResult = reader.result
    }
    reader.onerror = function (error) {
    
    
      reject(error)
    }
    reader.onloadend = function () {
    
    
      resolve(imgResult)
    }
  })
}
// 将base64转换为文件
export const dataURLtoFile = (dataurl, filename) => {
    
    
  let arr = dataurl.split(',')
  let bstr = atob(arr[1])
  let n = bstr.length
  let u8arr = new Uint8Array(n)
  while (n--) {
    
    
    u8arr[n] = bstr.charCodeAt(n)
  }
  return new File([u8arr], filename + '.jpeg', {
    
     type: 'image/jpeg' })
}