vue 将file图像文件转base64

imageToBase64 (file) {
      var reader = new FileReader()
      reader.readAsDataURL(file)
      reader.onload = () => {
        console.log('file 转 base64结果：' + reader.result)
        this.iconBase64 = reader.result
      }
      reader.onerror = function (error) {
        console.log('Error: ', error)
}