elementui上传图片校验

<el-form-item label="门店海报：" prop="imageUrl" ref="image">
//自定义正则
var valiIcon = (rule, value, callback) => {
      // 图片验证
      if (!this.hasFmt) { //hasFmt设置为true/false
        callback(new Error("请上传门店海报"));
      } else {
        callback();
      }
//rules
imageUrl: [{ required: true, validator: valiIcon }]

//上传成功
handleAvatarSuccess(res) {
      this.hasFmt = true;
      this.$refs.image.clearValidate();
},
//删除成功
handleRemove(file) {
      this.hasFmt = false;
      this.$refs.image.validate();
    }