form 表单恢复初始数据

写表单的时候，想做到，某个操作时，表单恢复初始数据

this.$options.data().form form 是表单的对象

<template>
  <div>
    <el-dialog title="提示" :visible.sync="dialogVisible">
      <el-form :model="form" ref="form">
        <el-form-item label="用户名称1">
          <el-input v-model="form.aaa" class="w-200"></el-input>
        </el-form-item>
        <el-form-item label="用户名2">
          <el-input v-model="form.bbb" class="w-200"></el-input>
        </el-form-item>
        <el-form-item label="用户名称3">
          <el-input v-model="form.ccc" class="w-200"></el-input>
        </el-form-item>
        <el-form-item label="否，则清空数据">
          <el-radio-group v-model="form.ddd" @change="btn">
            <el-radio :label="1">是</el-radio>
            <el-radio :label="2">否</el-radio>
          </el-radio-group>
        </el-form-item>
      </el-form>
    </el-dialog>

    <el-button type="primary" @click="dialogVisible = true">按钮</el-button>
  </div>
</template>

<script>
export default {
  data () {
    return {
      dialogVisible: false,
      form: {
        aaa: '',
        bbb: '',
        ccc: '',
        ddd: ''
      }
    }
  },
  methods: {
    btn (val) {
      if (val === 2) {
        this.form = this.$options.data().form
        this.form.ddd = 2
      }
    }
  }
}
</script>

<style>
</style>