Буфер — blob, URL-адрес, base64

res为Буфер

Буфер в blbo

const blob = new Blob([res])

blbo на URL

const blobUrl = window.URL.createObjectURL(blob)

буфер в base64

    arrayBufferToBase64 (buffer) {
    
    
      var binary = ''
      var bytes = new Uint8Array(buffer)
      var len = bytes.byteLength
      for (var i = 0; i < len; i++) {
    
    
        binary += String.fromCharCode(bytes[i])
      }
      return window.btoa(binary)
    },

//图片
const base64Str = 'data:image/jpeg;base64,' + this.arrayBufferToBase64(res)
//pdf
const base64Str = 'data:application/pdf;base64,' + this.arrayBufferToBase64(res)