vue图片转base64

 // 转换成base64方法
      getBase64(file) {
        return new Promise(function (resolve, reject) {
          const 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);
          };
        });
      },
      beforeAvatarUpload(file) {
        this.getBase64(file.raw).then((res) => {
          this.form.enterpriseImage = res;
        });
      },