通过@hook:mounted 子组件mounted之后，会调用此函数。这个函数中可以通过ref调该子组件。

<template><div><WQuery @hook:mounted="childMounted"></WQuery></div>
</template>
<script>
import coms from "@/components/async.js";
export default {mounted() {console.log(this.$refs.form);},components: {...coms},methods: {childMounted () {alert('childMounted')},},
};
</script>