Vue2. X opens composition API and TSX

front end 2021-05-03 13:14:43
vue2. vue opens composition api


Preface

  1. I guess you might be a more biased one React developer
  2. I guess you may feel deeply Hooks It brings Logic reuse 、 Responsive programming All kinds of conveniences
  3. I guess you may be deeply dependent on Typescript, I like it very much JSX The power of expression
  4. I guess your company uses Vue2, Although the Vue3 You can use all the above benefits ; But you have to maintain Vue2 Old projects
  5. I guess you're upset , I want to learn Vue3 Bring new features , I want to reconstruct the existing Vue2 But it's too expensive
  6. I guess if you go on like this , Maybe I want to run away ~
  7. ...
  • Purpose This article is from React User perspective takes you to unlock Vue2 In the open Composition API And use TSX The mode of land development
  • hope This article can help you Don't panic , You can continue to treat

The goal is

  • Use Vue2 Project template added Composition API plug-in unit
  • Turn on .ts.tsx Support

Initialize project

A little ~

Join in Composition API plugin

  • Add dependency
yarn add @vue/composition-api
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Turn on ts、tsx Support

This project uses Babel@7.x

  • Add dependency

    yarn add -D @vue/babel-preset-jsx @vue/babel-helper-vue-jsx-merge-props @babel/plugin-transform-typescript
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  • Modify the configuration file

    • Modify root babel.config.js

      module.exports = {
      presets: [
      '@vue/cli-plugin-babel/preset',
      + ['@vue/babel-preset-jsx', { compositionAPI: true }], // Turn on jsx
      ],
      + plugins: [
      + ['@babel/plugin-transform-typescript', { isTSX: true }], // Turn on typescript
      + ],
      }
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    • New root vue.config.js

      + const path = require('path')
      + module.exports = {
      + configureWebpack: {
      + resolve: {
      + alias: {
      + '@': path.resolve(__dirname, './src'),
      + },
      + extensions: ['.ts', '.tsx'],
      + },
      + module: {
      + rules: [
      + {
      + test: /\.(jsx|tsx|ts)$/,
      + loader: 'babel-loader',
      + },
      + ],
      + },
      + },
      + }
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    • New root tsconfig.json

      + {
      + "compilerOptions": {
      + "target": "ES2017",
      + "module": "UMD",
      + "allowJs": true,
      + "jsx": "preserve",
      + "moduleResolution": "Node",
      + "allowSyntheticDefaultImports": true,
      + "importHelpers": true,
      + "baseUrl": "./",
      + "paths": {
      + "@/*": ["src/*"]
      + }
      + }
      + }
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modify App.vue -> App.tsx

  • .vue Document and .tsx It can be regarded as equivalent , It can be used directly ; Be careful jsx The first letter of the component label must be capitalized !

  • .png Static resource usage is to introduce , Through the bottom layer url-loader Handle ;@vue/cli Integrated static resource configuration

    import { defineComponent, onMounted } from '@vue/composition-api'
    import HelloWorld from './components/HelloWorld.vue'
    import logo from '@/assets/logo.png'
    export default defineComponent({
    setup() {
    onMounted(() => {})
    },
    render() {
    return (
    <div class="app">
    <img alt="Vue logo" src={logo} />
    <HelloWorld msg="Welcome to Your Vue.js App"/>
    </div>
    )
    },
    })
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  • Be careful !setup China does not support it. (setup There is no this) tsx, Must be written in render in

  • Start the project and see the effect ~

    yarn serve
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Notes

  • complete Demo stamp github
  • Demo Use API https://api.github.com/users
  • User The definition is as follows
    export interface User {
    avatar_url: string
    events_url: string
    followers_url: string
    following_url: string
    gists_url: string
    gravatar_id: string
    html_url: string
    id: number
    login: string
    node_id: string
    organizations_url: string
    received_events_url: string
    repos_url: string
    site_admin: boolean
    starred_url: string
    subscriptions_url: string
    type: string
    url: string
    }
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Write a Component

import { Row, Col, Image } from 'vant'
export default defineComponent({
props: {
users: {
type: Array as { (): User[] }, // Provide the type at the call to 
default: [],
},
},
render() {
return (
<Row class="img-box">
{this.users.map((user, idx) => (
<Col
class="img-item"
key={idx}
span={8}
// onclick Both upper and lower case are OK
// It's directly used here Vue2 Built in $emit than React ” slightly “ It's convenient
onclick={() => this.$emit('click', user)}
>
<Image src={user.avatar_url} />
<div>{user.login}</div>
</Col>
))}
</Row>
)
},
})
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Write a Hooks

  • If you did React Hooks So you probably know how to write it

  • It looks like a normal Functional expression Components , The general functional component returns VNode,Hooks return state

    // React Hooks
    import { useState, useEffect } from 'react'
    export function useRequestWithReact() {
    const [users, setUsers] = useState([])
    useEffect(() => {
    fetch('https://api.github.com/users')
    .then(_ => _.json())
    .then(data => {
    setUsers(users)
    })
    }, [])
    return { users }
    }
    // usage
    export default () => {
    const { users } = useRequestWithReact()
    return users.map(user =>
    <div key={user.id}>{user.login}</div>
    )
    }
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    // Vue2 Hooks
    import { ref } from '@vue/composition-api'
    export function useRequestWithVue2() {
    const users = ref([])
    fetch('https://api.github.com/users')
    .then(_ => _.json())
    .then(data => {
    users.value = data
    })
    return { users }
    }
    // usage
    export default () => {
    const { users } = useRequestWithVue2()
    return users.map(user =>
    <div key={user.id}>{user.login}</div>
    )
    }
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  • These two frames are Hooks/Composition API The design is really similar , Just like now Android and iOS System

    And React Hooks Comparison of

     On the whole, it's more in line with JavaScript Intuition ;
    Not limited by the order of calls , Can be conditionally called ;
    It will not produce a large number of inline functions in subsequent updates, which will affect engine optimization or cause GC pressure ;
    It doesn't need to be used all the time useCallback To cache callbacks passed to subcomponents to prevent over updating ;
    Don't worry about passing the wrong dependency array to useEffect/useMemo/useCallback This results in the use of expired values in the callback —— Vue Dependency tracking for is fully automatic .
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Write a Hooks with Component

How and why?

  • Just imagine we write a Component

    • earnings : Can reuse UI Exhibition , The interior can have its own logic 、 state
    • disadvantages : Internal logic 、 Status external communication There needs to be some means Handle ,Vue、React All is so
  • Just imagine we write a Hooks

    • earnings : Provide logic 、 The status is automatically updated
  • Can you put the Hooks、Component Put all the benefits together ?( The choice of the adult world is ) Function Component、Hooks It's just that the return value looks different ; If we “ Both return to ” What about? ?

    • earnings : Can reuse UI Exhibition , The interior can have its own logic 、 state With the help of responsive design Automatically spit out Internal state Instead of using various communication methods of components to Pull it out by hand Internal state
  • be based on vant To design a useCalendar

    // src/hooks/useCalendar.tsx
    import { ref } from '@vue/composition-api'
    import { Calendar } from 'vant'
    export default function () {
    const visble = ref(false)
    const date = ref()
    const onConfirm = (val) => {
    visble.value = false
    date.value = val
    }
    // You have to wrap it with functions 
    // because setup Not available in h function 
    // component It needs to be delivered to dome.tsx Of render Call in ,render Can be used in h function , And right this Point to 
    // The purpose of not using arrow functions is also to this The right direction of 
    // !!!
    // It's written in Vue3.x、React To be more simple 、 Easy to understand 
    // It is, after all, vue2 Plug in for , There are still some restrictions on writing 
    // !!!
    const component = function () {
    return <Calendar
    vModel={visble.value}
    onConfirm={onConfirm}
    />
    }
    return {
    visble,
    date,
    component,
    }
    }
    // src/views/dome.tsx
    import { defineComponent, watch, computed } from '@vue/composition-api'
    import { Button } from 'vant'
    export default defineComponent({
    setup() {
    const { date, visble, component } = useCalendar()
    watch(date, => {
    // Always execute automatically after selecting a date wath Of callback
    // Instead of manually fishing it out by means of communication 
    console.log(' The date you choose is :', date)
    })
    // perhaps computed(() => date -> do something...)
    return {
    visble,
    component,
    }
    },
    render() {
    return (
    <div>
    <Button onclick={() => this.visble = true}> Click on the date </Button>
    <hr/>
    {this.component()}
    </div>
    )
    },
    })
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Hooks with Component

  • thus , We can answer Hooks I want to ask you a question :“Hooks Besides logic reuse , Also can realize UI Reuse ” I believe you should encapsulate some scenes in your work Component still Hooks There will be a new reference

Personal about Vue Of Composition API view

  • Design is closer to Responsive programming It's like there's no operator Of rxjs; It smells like that ~
  • ref、reactive Data source is Observable object ; Templates componentwatch These can be considered subscribers
  • watch、watchEffect Design and design mobx Medium reaction、autorun The behavior is basically the same

Personal about React Of Hooks view

  • React Of Hooks stay setState And then call the current component repeatedly ( function ), By executing... Within the current component useEffect、useMemo And compare deps Decide whether to “ Respond to ”; Simulated Response type Design
  • Quote from the official website ~ ( Maybe you have noticed )

React Hooks

VSCode To configure

  • emmet Generate class instead of className
    {
    "emmet.includeLanguages": {
    "javascriptreact": "html",
    "typescriptreact": "html"
    }
    }
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Reference article

版权声明
本文为[front end]所创,转载请带上原文链接,感谢
https://qdmana.com/2021/05/20210503131221593H.html

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