Vue 3 如何获取有关 $children 的信息

Question

这是我在 Tabs 组件中使用 VUE 2 的旧代码：

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

标签：

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

VUE 3：如何使用组合 API 在 Tabs 组件中获取有关儿童的一些信息？获取长度，迭代它们，并创建标签页眉，......等等？有任何想法吗？（使用组合 API）

Answer 1

哦，伙计们，我解决了它：

slots.default().filter(child => child.type.name === 'Tab')

Answer 2

我扫描子元素的解决方案（在对 vue 代码进行了大量筛选之后）是这样的。

export function findChildren(parent, matcher) {
  const found = [];
  const root = parent.$.subTree;
  walk(root, child => {
    if (!matcher || matcher.test(child.$options.name)) {
      found.push(child);
    }
  });
  return found;
}

function walk(vnode, cb) {
  if (!vnode) return;

  if (vnode.component) {
    const proxy = vnode.component.proxy;
    if (proxy) cb(vnode.component.proxy);
    walk(vnode.component.subTree, cb);
  } else if (vnode.shapeFlag & 16) {
    const vnodes = vnode.children;
    for (let i = 0; i < vnodes.length; i++) {
      walk(vnodes[i], cb);
    }
  }
}

这将返回子组件。我对此的用途是我有一些通用的对话框处理代码，用于搜索子表单元素组件以查询其有效性状态。

const found = findChildren(this, /^(OSelect|OInput|OInputitems)$/);
const invalid = found.filter(input => !input.checkHtml5Validity());

Answer 3

现在这是我的 Vue 3 组件。我使用提供来获取子Tab组件中的信息。

<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>

标签组件：

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};
  }
});


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

Answer 4

如果你复制粘贴与我相同的代码

然后只需向“tab”组件添加一个创建的方法，该方法将自身添加到其父级的 tabs 数组中

created() {
    
        this.$parent.tabs.push(this); 

    },

Answer 5

通过脚本设置语法，您可以使用useSlots：https://vuejs.org/api/sfc-script-setup.html#useslots-useattrs

<script setup>
import { useSlots, ref, computed } from 'vue';

const props = defineProps({
    perPage: {
        type: Number,
        required: true,
    },
});

const slots = useSlots();

const amountToShow = ref(props.perPage);
const totalChildrenCount = computed(() => slots.default()[0].children.length);
const childrenToShow = computed(() => slots.default()[0].children.slice(0, amountToShow.value));
</script>

<template>
    <component
        :is="child"
        v-for="(child, index) in childrenToShow"
        :key="`show-more-${child.key}-${index}`"
    ></component>
</template>

Answer 6

对于想要完整代码的人：

标签页

<template>
    <div>
        <div class="tabs">
            <ul>
                <li v-for="tab in tabs" :class="{ 'is-active': tab.isActive }">
                    <a :href="tab.href" @click="selectTab(tab)">{{ tab.name }}</a>
                </li>
            </ul>
        </div>

        <div class="tabs-details">
            <slot></slot>
        </div>
    </div>
</template>

<script>
    export default {
        name: "Tabs",
        data() {
            return {tabs: [] };
        },
        created() {

        },
        methods: {
            selectTab(selectedTab) {
                this.tabs.forEach(tab => {
                    tab.isActive = (tab.name == selectedTab.name);
                });
            }
        }
    }
</script>

<style scoped>

</style>

Tab.vue

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

<script>
    export default {
        name: "Tab",
        props: {
            name: { required: true },
            selected: { default: false}
        },

        data() {

            return {
                isActive: false
            };

        },

        computed: {

            href() {
                return '#' + this.name.toLowerCase().replace(/ /g, '-');
            }
        },

        mounted() {

            this.isActive = this.selected;

        },

        created() {

            this.$parent.tabs.push(this);

        },
    }
</script>

<style scoped>

</style>

应用程序.js

<template>
    <Tabs>
                    <Tab :selected="true"
                         :name="'a'">
                        aa
                    </Tab>
                    <Tab :name="'b'">
                        bb
                    </Tab>
                    <Tab :name="'c'">
                        cc
                    </Tab>
                </Tabs>
<template/>