<template>
  <el-form ref="form" :model="form" :rules="rules">
    <el-form-item label="封面" prop="cover">
      <el-upload class="upload-demo" v-model="form.cover">
        <el-button size="small" type="primary">点击上传</el-button>
      </el-upload>
    </el-form-item>
  </el-form>
</template>
<script>
export default {
  name: 'Demo',
  data() {
    const validateLogo = (rule, value, callback) => {
      if (!this.form.cover) {
        callback(new Error('请上传图片'))
      } else {
        callback()
      }
    }
    return {
      form: {
        cover: null,
      },
      rules: {
        cover: [{ required: true, validator: validateLogo, trigger: 'change' }],
      },
    }
  },

  methods: {
    upload(formName) {
      this.$refs[formName].validate((valid) => {
        if (valid) {
          //  验证完后
        }
      })
    },
  },
}
</script>