Details of 7 kinds of component communication in Vue3

// Parent.vue transmits <child :msg1="msg1" :msg2="msg2"></child>
<script>
import child from "./child.vue"
import { ref, reactive } from "vue"
export default {
    data(){
        return {
            msg1: "This is the information of the sub-component 1"
        }
    },
    setup(){
        // Create a responsive data // Writing method 1 is applicable to the basic type ref and has other uses. The following chapter introduces const msg2 = ref("This is the information of the subcomponent 2")
        
        // Method 2 is suitable for complex types, such as arrays and objects const msg2 = reactive(["This is the information of the subcomponent 2"])
        
        return {
            msg2
        }
    }
}
</script>

// Child.vue receives <script>
export default {
  props: ["msg1", "msg2"], // If this line is not written, the following will not receive setup(props) {
    console.log(props) // { msg1: "This is information 1 passed to the child component", msg2: "This is information 2 passed to the child component" }
  },
}
</script>

// Parent.vue transmits <child :msg2="msg2"></child>
<script setup>
    import child from "./child.vue"
    import { ref, reactive } from "vue"
    const msg2 = ref("This is the information passed to the child component 2")
    // or complex type const msg2 = reactive(["This is the information of the subcomponent 2"])
</script>

// Child.vue receives <script setup>
    // No need to import directly // import { defineProps } from "vue"
    const props = defineProps({
        //Writing method 1 msg2: String
        //Writing method 2 msg2:{
            type:String,
            default:""
        }
    })
    console.log(props) // { msg2: "This is the information of the subcomponent 2" }
</script>

// Parent.vue responds to <template>
    <child @myClick="onMyClick"></child>
</template>
<script setup>
    import child from "./child.vue"
    const onMyClick = (msg) => {
        console.log(msg) // This is the information received by the parent component}
</script>

// Child.vue
<script setup>
    // Method 1 is not applicable to Vue 3.2, in which useContext() is deprecated import { useContext } from "vue"
    const ctx = useContext()
    // Externally exposed properties and methods can be ctx.expose({
        childName: "This is a property of the child component",
        someMethod(){
            console.log("This is the method of the child component")
        }
    })
    
    // Method 2 is applicable to Vue 3.2 version, no need to import // import { defineExpose } from "vue"
    defineExpose({
        childName: "This is a property of the child component",
        someMethod(){
            console.log("This is the method of the child component")
        }
    })
</script>

// Parent.vue Note ref="comp"
<template>
    <child ref="comp"></child>
    <button @click="handlerClick">Button</button>
</template>
<script setup>
    import child from "./child.vue"
    import { ref } from "vue"
    const comp = ref(null)
    const handlerClick = () => {
        console.log(comp.value.childName) // Get the properties exposed by the child component comp.value.someMethod() // Call the method exposed by the child component }
</script>

// Parent.vue transmits <child :msg1="msg1" :msg2="msg2" title="3333"></child>
<script setup>
    import child from "./child.vue"
    import { ref, reactive } from "vue"
    const msg1 = ref("1111")
    const msg2 = ref("2222")
</script>

// Child.vue receives <script setup>
    import { defineProps, useContext, useAttrs } from "vue"
    // Version 3.2 does not need to introduce defineProps, just use const props = defineProps({
        msg1: String
    })
    // Method 1 is not applicable to Vue 3.2, where useContext() is deprecated const ctx = useContext()
    // If msg1 is not received using props, it will be { msg1: "1111", msg2: "2222", title: "3333" }
    console.log(ctx.attrs) // { msg2:"2222", title: "3333" }
    
    // Method 2 is applicable to Vue 3.2 version const attrs = useAttrs()
    console.log(attrs) // { msg2:"2222", title: "3333" }
</script>

// Parent.vue
<child v-model:key="key" v-model:value="value"></child>
<script setup>
    import child from "./child.vue"
    import { ref, reactive } from "vue"
    const key = ref("1111")
    const value = ref("2222")
</script>

// Child.vue
<template>
    <button @click="handlerClick">Button</button>
</template>
<script setup>
    
    // Method 1 is not applicable to Vue 3.2, in which useContext() is deprecated import { useContext } from "vue"
    const { emit } = useContext()
    
    // Method 2 is applicable to Vue 3.2 version and does not need to be introduced // import { defineEmits } from "vue"
    const emit = defineEmits(["key","value"])
    
    // Usage const handlerClick = () => {
        emit("update:key", "new key")
        emit("update:value", "new value")
    }
</script>

// Parent.vue
<script setup>
    import { provide } from "vue"
    provide("name", "Muhua")
</script>

// Child.vue
<script setup>
    import { inject } from "vue"
    const name = inject("name")
    console.log(name) // Mu Hua</script>

// store/index.js
import { createStore } from "vuex"
export default createStore({
    state:{ count: 1 },
    getters:{
        getCount: state => state.count
    },
    mutations:
        add(state){
            state.count++
        }
    }
})

// main.js
import { createApp } from "vue"
import App from "./App.vue"
import store from "./store"
createApp(App).use(store).mount("#app")

// Page.vue
// Method 1: Use <template> directly
    <div>{{ $store.state.count }}</div>
    <button @click="$store.commit('add')">Button</button>
</template>

// Method 2 to get <script setup>
    import { useStore, computed } from "vuex"
    const store = useStore()
    console.log(store.state.count) // 1

    const count = computed(()=>store.state.count) // Responsive, will change as vuex data changes console.log(count) // 1 
</script>