Vue 3 how to get information about $children

Question

This my old code with VUE 2 in Tabs component:

created() {
   this.tabs = this.$children;
}

Tabs:

<Tabs> 
  <Tab title="tab title">
    ....
  </Tab>
  <Tab title="tab title">
    ....
  </Tab> 
</Tabs>

VUE 3: How can I get some information about childrens in Tabs component, using composition API? Get length, iterate over them, and create tabs header, ...etc? Any ideas? (using composition API)

Answer 1

This is my Vue 3 component now. I used provide to get information in child Tab component.

<template>
  <div class="tabs">
    <div class="tabs-header">
      <div
        v-for="(tab, index) in tabs"
        :key="index"
        @click="selectTab(index)"
        :class="{'tab-selected': index === selectedIndex}"
        class="tab"
      >
        {{ tab.props.title }}
      </div>
    </div>
    <slot></slot>
  </div>
</template>

<script lang="ts">
import {defineComponent, reactive, provide, onMounted, onBeforeMount, toRefs, VNode} from "vue";
    
interface TabProps {
  title: string;
}
    
export default defineComponent({
  name: "Tabs",
  setup(_, {slots}) {
    const state = reactive({
      selectedIndex: 0,
      tabs: [] as VNode<TabProps>[],
      count: 0
    });
    
    provide("TabsProvider", state);
    
    const selectTab = (i: number) => {
      state.selectedIndex = i;
    };
    
    onBeforeMount(() => {
      if (slots.default) {
        state.tabs = slots.default().filter((child) => child.type.name === "Tab");
      }
    });

    onMounted(() => {
      selectTab(0);
    });

    return {...toRefs(state), selectTab};
  }
});
</script>

Tab component:

<script lang="ts">
export default defineComponent({
  name: "Tab",
  setup() {
    const index = ref(0);
    const isActive = ref(false);

    const tabs = inject("TabsProvider");

    watch(
      () => tabs.selectedIndex,
      () => {
        isActive.value = index.value === tabs.selectedIndex;
      }
    );

    onBeforeMount(() => {
      index.value = tabs.count;
      tabs.count++;
      isActive.value = index.value === tabs.selectedIndex;
    });
    return {index, isActive};
  }
});
</script>

<template>
  <div class="tab" v-show="isActive">
      <slot></slot>
  </div>
</template>