element-ui form表单上传图片校验

<el-form-item label="桌台二维码" prop="coverPic" ref="image">
          <el-upload
            :http-request="uploadFile"
            action=""
            :on-success="handleSuccessForm"
            :show-file-list="false"
            accept=".png,.jpg,.jpeg,.gif"
            :before-upload="beforeAvatarUpload"
          >
            <img width="200" height="150" v-if="ruleForm.coverPic" :src="ruleForm.coverPic" class="radius10" />
            <div v-else>
              <div class="imgUploadWraper">
                <el-button slot="trigger" size="mini" type="primary">上传二维码</el-button>
              </div>
            </div>
          </el-upload>
          <p style="margin: 0">格式支持jpg/png/gif，最大5MB，建议尺寸60*60</p>
        </el-form-item>

    let valiIcon = (rule, value, callback) => {
      if (!this.valiIconFlag) {
        callback(new Error('请上传分类图'))
      } else {
        callback()
      }
    }

coverPic: [{ required: true, validator: valiIcon }],

//上传成功
handleSuccessForm() {
      this.valiIconFlag = true
      this.$refs.image.clearValidate()
      this.$message.success('上传成功')
    },

//删除成功
handleRemove(file) {
      this.valiIconFlag = false; 
this.$refs.image.validate(); 
}