Vue使用Element折叠面板Collapse如何设置默认全部展开

<el-collapse :value="opened">
  <el-collapse-item v-for="o in List" :key="o.aaa":name="o.aaa">
    <div>XXXXXXXXXXXXXXXXXXXXXXXX</div>
  </el-collapse-item>
</el-collapse>
 
<script>
  export default {
    data() {
      return {
           List:[
               { 
                   aaa:"123"
               },
               {
                   aaa:"354"
               },
               {
                   aaa:"asfdvg"
               }
           ]
      };
    },
      computed: {
            opened() {
                return this.List.map((i) => {
                    return i.aaa;
                });
            }
        },
  }
</script>

const elTransition =
  "0.3s height ease-in-out, 0.3s padding-top ease-in-out, 0.3s padding-bottom ease-in-out";
const Transition = {
  "before-enter"(el) {
    el.style.transition = elTransition;
    if (!el.dataset) el.dataset = {};
 
    el.dataset.oldPaddingTop = el.style.paddingTop;
    el.dataset.oldPaddingBottom = el.style.paddingBottom;
 
    el.style.height = 0;
    el.style.paddingTop = 0;
    el.style.paddingBottom = 0;
  },
 
  enter(el) {
    el.dataset.oldOverflow = el.style.overflow;
    if (el.scrollHeight !== 0) {
      el.style.height = el.scrollHeight + "px";
      el.style.paddingTop = el.dataset.oldPaddingTop;
      el.style.paddingBottom = el.dataset.oldPaddingBottom;
    } else {
      el.style.height = "";
      el.style.paddingTop = el.dataset.oldPaddingTop;
      el.style.paddingBottom = el.dataset.oldPaddingBottom;
    }
 
    el.style.overflow = "hidden";
  },
 
  "after-enter"(el) {
    el.style.transition = "";
    el.style.height = "";
    el.style.overflow = el.dataset.oldOverflow;
  },
 
  "before-leave"(el) {
    if (!el.dataset) el.dataset = {};
    el.dataset.oldPaddingTop = el.style.paddingTop;
    el.dataset.oldPaddingBottom = el.style.paddingBottom;
    el.dataset.oldOverflow = el.style.overflow;
 
    el.style.height = el.scrollHeight + "px";
    el.style.overflow = "hidden";
  },
 
  leave(el) {
    if (el.scrollHeight !== 0) {
      el.style.transition = elTransition;
      el.style.height = 0;
      el.style.paddingTop = 0;
      el.style.paddingBottom = 0;
    }
  },
 
  "after-leave"(el) {
    el.style.transition = "";
    el.style.height = "";
    el.style.overflow = el.dataset.oldOverflow;
    el.style.paddingTop = el.dataset.oldPaddingTop;
    el.style.paddingBottom = el.dataset.oldPaddingBottom;
  }
};
 
export default {
  name: "collapseTransition",
  functional: true,
  render(h, { children }) {
    const data = {
      on: Transition
    };
    return h("transition", data, children);
  }
};

<template>
    <div class="container">
        <button @click="isActive = !isActive">展开/折叠</button>
        <collapse>
            <div v-show="isActive">
                <div style="border:1px solid #DDD;padding:10px;">
                <h2>欢迎大家品尝Pizza!</h2>
                <h5>这里有你非常喜欢的Pizza!</h5>
                </div>
            </div>
        </collapse>
        <div>
            666
        </div>
    </div>
</template>
<script>
import collapse from "#/assets/js/collapse.js";
export default {
  data() {
    return {
      isActive: false
    };
  },
  components: {
    collapse
  }
};
</script>