父组件通过v-bind绑定一个数据，然后子组件通过defineProps接受传过来的值，

如以下代码

给Menu组件 传递了一个title 字符串类型是不需要v-bind

<template>
    <div class="layout">
        <Menu  title="我是标题"></Menu>
        <div class="layout-right">
            <Header></Header>
            <Content></Content>
        </div>
    </div>
</template>

传递非字符串类型需要加v-bind  简写 冒号

<template>
    <div class="layout">
        <Menu v-bind:data="data"  title="我是标题"></Menu>
        <div class="layout-right">
            <Header></Header>
            <Content></Content>
        </div>
    </div>
</template>

<script setup lang="ts">
import Menu from './Menu/index.vue'
import Header from './Header/index.vue'
import Content from './Content/index.vue'
import { reactive } from 'vue';

const data = reactive<number[]>([1, 2, 3])
</script>

子组件接受值

通过defineProps 来接受 defineProps是无须引入的直接使用即可

如果我们使用的TypeScript

可以使用传递字面量类型的纯类型语法做为参数

如 这是TS特有的

<template>
    <div class="menu">
        菜单区域 {{ title }}
        <div>{{ data }}</div>
    </div>
</template>

<script setup lang="ts">
defineProps<{
    title:string,
    data:number[]
}>()
</script>

如果你使用的不是TS

defineProps({
    title:{
        default:"",
        type:string
    },
    data:Array
})

TS 特有的默认值方式

withDefaults是个函数也是无须引入开箱即用接受一个props函数第二个参数是一个对象设置默认值

type Props = {
    title?: string,
    data?: number[]
}
withDefaults(defineProps<Props>(), {
    title: "张三",
    data: () => [1, 2, 3]
})

子组件给父组件传参

是通过defineEmits派发一个事件

<template>
    <div class="menu">
        <button @click="clickTap">派发给父组件</button>
    </div>
</template>

<script setup lang="ts">
import { reactive } from 'vue'
const list = reactive<number[]>([4, 5, 6])

const emit = defineEmits(['on-click'])

//如果用了ts可以这样两种方式
// const emit = defineEmits<{
//     (e: "on-click", name: string): void
// }>()
const clickTap = () => {
    emit('on-click', list)
}

</script>

我们在子组件绑定了一个click 事件 然后通过defineEmits 注册了一个自定义事件

点击click 触发 emit 去调用我们注册的事件 然后传递参数

父组件接受子组件的事件

<template>
    <div class="layout">
        <Menu @on-click="getList"></Menu>
        <div class="layout-right">
            <Header></Header>
            <Content></Content>
        </div>
    </div>
</template>

<script setup lang="ts">
import Menu from './Menu/index.vue'
import Header from './Header/index.vue'
import Content from './Content/index.vue'
import { reactive } from 'vue';

const data = reactive<number[]>([1, 2, 3])

const getList = (list: number[]) => {
    console.log(list,'父组件接受子组件');
}
</script>

我们从Menu 组件接受子组件派发的事件on-click 后面是我们自己定义的函数名称getList

会把参数返回过来

子组件暴露给父组件内部属性

通过defineExpose

我们从父组件获取子组件实例通过ref

 <Menu ref="refMenu"></Menu>
//这样获取是有代码提示的
<script setup lang="ts">
import MenuCom from '../xxxxxxx.vue'
//注意这儿的typeof里面放的是组件名字(MenuCom)不是ref的名字 ref的名字对应开头的变量名(refMenu)
const refMenu = ref<InstanceType<typeof MenuCom>>()
</script>
 

然后打印menus.value 发现没有任何属性

这时候父组件想要读到子组件的属性可以通过 defineExpose暴露

const list = reactive<number[]>([4, 5, 6])

defineExpose({
    list
})

这样父组件就可以读到了

案例封装瀑布流组件

父组件

<template>
    <waterFallVue :list="list"></waterFallVue>
</template>

<script setup lang='ts'>
import { ref, reactive } from 'vue'
import waterFallVue from './components/water-fall.vue';
const list = [
    {
        height: 300,
        background: 'red'
    },
    {
        height: 400,
        background: 'pink'
    },
    {
        height: 500,
        background: 'blue'
    },
    {
        height: 200,
        background: 'green'
    },
    {
        height: 300,
        background: 'gray'
    },
    {
        height: 400,
        background: '#CC00FF'
    },
    {
        height: 200,
        background: 'black'
    },
    {
        height: 100,
        background: '#996666'
    },
    {
        height: 500,
        background: 'skyblue'
    },
    {
        height: 300,
        background: '#993366'
    },
    {
        height: 100,
        background: '#33FF33'
    },
    {
        height: 400,
        background: 'skyblue'
    },
    {
        height: 200,
        background: '#6633CC'
    },
    {
        height: 300,
        background: '#666699'
    },
    {
        height: 300,
        background: '#66CCFF'
    },
    {
        height: 300,
        background: 'skyblue'
    },
    {
        height: 200,
        background: '#CC3366'
    },
    {
        height: 200,
        background: '#CC9966'
    },
    {
        height: 200,
        background: '#FF00FF'
    },
    {
        height: 500,
        background: '#990000'
    },
    {
        height: 400,
        background: 'red'
    },
    {
        height: 100,
        background: '#999966'
    },
    {
        height: 200,
        background: '#CCCC66'
    },
    {
        height: 300,
        background: '#FF33FF'
    },
    {
        height: 400,
        background: '#FFFF66'
    },
    {
        height: 200,
        background: 'red'
    },
    {
        height: 100,
        background: 'skyblue'
    },
    {
        height: 200,
        background: '#33CC00'
    },
    {
        height: 300,
        background: '#330033'
    },
    {
        height: 100,
        background: '#0066CC'
    },
    {
        height: 200,
        background: 'skyblue'
    },
    {
        height: 100,
        background: '#006666'
    },
    {
        height: 200,
        background: 'yellow'
    },
    {
        height: 300,
        background: 'yellow'
    },
    {
        height: 100,
        background: '#33CCFF'
    },
    {
        height: 400,
        background: 'yellow'
    },
    {
        height: 400,
        background: 'yellow'
    },
    {
        height: 200,
        background: '#33FF00'
    },
    {
        height: 300,
        background: 'yellow'
    },
    {
        height: 100,
        background: 'green'
    }

]
</script>

<style  lang='less'>
#app,
html,
body {
    height: 100%;
}

* {
    padding: 0;
    margin: 0;
}
</style>

 子组件

<template>
    <div class="wraps">
        <div :style="{height:item.height+'px',background:item.background,top:item.top+'px',left:item.left + 'px'}"
            v-for="item in waterList" class="items"></div>
    </div>
</template>

<script setup lang='ts'>
import { ref, reactive, onMounted } from 'vue'
const props = defineProps<{
    list: any[]
}>()
const waterList = reactive<any[]>([])
const init = () => {
    const heightList: any[] = []
    const width = 130;
    const x = document.body.clientWidth
    const column = Math.floor(x / width)

    for (let i = 0; i < props.list.length; i++) {
        if (i < column) {
            props.list[i].top = 10;
            props.list[i].left = i * width;
            heightList.push(props.list[i].height + 10)
            waterList.push(props.list[i])
        } else {
            let current = heightList[0]
            let index = 0;
            heightList.forEach((h, inx) => {
                if (current > h) {
                    current = h;
                    index = inx;
                }
            })
            console.log(current,'c')
            props.list[i].top = (current + 20);
            console.log(props.list[i].top,'top',i)
            props.list[i].left = index * width;
            heightList[index] =  (heightList[index] + props.list[i].height + 20);
            waterList.push(props.list[i])
        
        }
    }
    console.log(props.list)
}

onMounted(() => {
    window.onresize = () => init()
    init()
})

</script>

<style scoped lang='less'>
.wraps {
    position: relative;
     height: 100%;
    .items {
        position: absolute;
        width: 120px;
    }
}
</style>