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Vue3 - advanced experience [3]
2022-01-29 15:23:58 【Hisen】
Preface
The first two chapters share the use of Vue3 How to create a technology stack project to get started quickly , After reading and practicing , In theory, there is no problem to start the project directly .
In this article, I mainly want to share three knowledge points
- Fragment
vue3 Add default implicit label
- Teleport
One that can bring us html Technology of structural teleportation
- script setup
Vue Experimental writing proposed by the team
Fragment
In the previous chapter , Pay attention to the children's shoes that have seen the code , I don't know if there is a small change in wood , stay Vue2 in , The component must have a root label , And in the Vue3 in , To optimize the , Components can have no root tag , Multiple tags will be included in one Fragment
In a virtual element , Children's shoes that have used document fragments can be understood as basically similar , Let's take a look at this code
<template>
<h2> {{refValue}}</h2>
<h3> {{ reactiveValue.name }} : {{ reactiveValue.age }} </h3>
</template>
<script> import { ref, reactive } from "vue"; export default { setup () { const refValue = ref(123); const reactiveValue = reactive({ name: " Xiao Na ", age: 17 }); return { refValue, reactiveValue }; }, }; </script>
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benefits
Reduce the label level , Reduce memory footprint
Teleport
Teleport yes Vue3 Provide a new technology , Place the inside of the component dom Elements , Blink to a certain position , Speaking in vernacular alone may not be so easy to understand , Let's use code to practice the specific effect
Teleport grammar
<Teleport to=" Where to move , Such as :body,id,class etc. ">
// ... Own elements
</Teleport>
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practice
<template>
<h2>{{reactiveObj.name}} - {{reactiveObj.demo}}</h2>
<h2 @click="isShow = true"> open </h2>
<!-- Notice the Teleport to body -->
<Teleport to="body"> <div class="tip" v-if="isShow"> <button @click="isShow = false"> close </button> <ul> <li v-for="i in 5" :key="i">{{i}}</li> </ul> </div> </Teleport>
</template>
<script> import { ref, reactive } from "vue" export default { setup () { let isShow = ref(false) let reactiveObj = reactive({ name: "Hisen", demo: "Vue3" }) return { isShow, reactiveObj } } } </script>
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The default class is tip
The element of is not displayed , And I wrote it inside a component , When I click Open , Class is tip
The element is displayed , Click close to close , In order to see the effect , I use the v-if
Teleport
According to the effect , It's amazing , Was moved to body End the label position , There is also a better one at this time tip
Element positioning is relative to body
Of , Thief Shuang ~
not used Teleport
General effects , It's still defining the position of the element
script setup understand
Why did I put an understanding on the title , Because so far Vue The team hasn't officially released the syntax yet , Just in the experimental stage , But whether it smells good or not , I can only tell you , One word sweet
!
script setup
It's a simplification setup Technical solution of function , Make the code more concise , Why do you say that? ? Let's review setup How to use
<template>
<h3>{{refValue}}</h3>
</template>
<script> import { ref } from "vue"; export default { setup () { let refValue = ref(123) return { refValue, }; } }; </script>
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I don't say much nonsense , I went straight to the last one script setup In the form of , Let's compare
<template>
<h3>{{refValue}}</h3>
</template>
<script setup> // Be careful import { ref, reactive } from "vue" let refValue = ref(123) </script>
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Found something ? stay script setup in , <script>
The label becomes <script setup>
, setup Functions no longer exist , Directly into a statement , And then ok 了 , You read that right , It's that simple , Then a wisp
Use variables and methods
<script setup>
import { ref } from "vue";
const refValue = ref("setup script");
const handlerClick = () => {
console.log("on click");
};
</script>
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Use components
All imported components will be registered automatically , You can use it directly
<script setup>
import childComp from "./components/childComp.vue";
import Button from "./components/Button.vue";
</script>
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Use props
stay script setup in , Need to use defineProps
To define , The specific usage is similar to props Is essentially the same
<script setup>
import { defineProps } from "vue";
const props = defineProps(['title', 'content']);
</script>
// to `props` Definition type
const props = defineProps({
title: String,
content: {
type: Stirng,
required: true
}
});
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Use context
Like a hooks Get slots , attrs
, Acquired slots
attrs
Just like before setup
What's in it is the same
import { useContext } from 'vue'
const { slots, attrs } = useContext()
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Use emit
stay script setup in , Need to use defineEmit
To define , The usage is no different from that before
import { defineEmit } from 'vue'
// 4, Defining events
const emit = defineEmit(['emitclick']);
// Triggering event
const emitclick = () => {
emit('myclick','params');
}
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The parent component listens and follows Vue2 equally
<template>
<HelloWorld msg="Hello Vue3" @myclick="onmyclick"/>
</template>
<script setup> import HelloWorld from './components/HelloWorld.vue'; const onmyclick = () => { console.log(" Child components helloword adopt emit Triggered events "); } </script>
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end
Generally speaking, these functions are very wow , especially setup script
, The code looks much simpler , The development efficiency is greatly improved . The only thing that's not beautiful is that it's still in the experimental stage
A little encouragement , Grow greatly , Welcome to thumb up , Collection
copyright notice
author[Hisen],Please bring the original link to reprint, thank you.
https://en.qdmana.com/2022/01/202201291523564142.html
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