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    vue-class-componentpublic

    vue-class-component

    ECMAScript / TypeScript decorator for class-style Vue components.

    npm

    Usage

    Required: ECMAScript stage 1 decorators. If you use Babel, babel-plugin-transform-decorators-legacy is needed. If you use TypeScript, enable --experimentalDecorators flag.

    It does not support the stage 2 decorators yet since mainstream transpilers still transpile to the old decorators.

    Note:

    1. methods can be declared directly as class member methods.

    2. Computed properties can be declared as class property accessors.

    3. Initial data can be declared as class properties (babel-plugin-transform-class-properties is required if you use Babel).

    4. data, render and all Vue lifecycle hooks can be directly declared as class member methods as well, but you cannot invoke them on the instance itself. When declaring custom methods, you should avoid these reserved names.

    5. For all other options, pass them to the decorator function.

    Example

    Following is the example written in Babel. If you are looking for TypeScript version, it's in the example directory.

    <template>
      <div>
        <input v-model="msg">
        <p>prop: {{propMessage}}</p>
        <p>msg: {{msg}}</p>
        <p>helloMsg: {{helloMsg}}</p>
        <p>computed msg: {{computedMsg}}</p>
        <button @click="greet">Greet</button>
      </div>
    </template>
     
    <script>
    import Vue from 'vue'
    import Component from 'vue-class-component'
     
    @Component({
      props: {
        propMessage: String
      }
    })
    export default class App extends Vue {
      // initial data
      msg = 123
     
      // use prop values for initial data
      helloMsg = 'Hello, ' + this.propMessage
     
      // lifecycle hook
      mounted () {
        this.greet()
      }
     
      // computed
      get computedMsg () {
        return 'computed ' + this.msg
      }
     
      // method
      greet () {
        alert('greeting: ' + this.msg)
      }
    }
    </script>

    You may also want to check out the @prop and @watch decorators provided by vue-property-decorators.

    Using Mixins

    vue-class-component provides mixins helper function to use mixins in class style manner. By using mixins helper, TypeScript can infer mixin types and inherit them on the component type.

    Example of declaring a mixin:

    // mixin.js
    import Vue from 'vue'
    import Component from 'vue-class-component'
     
    // You can declare a mixin as the same style as components.
    @Component
    export class MyMixin extends Vue {
      mixinValue = 'Hello'
    }

    Example of using a mixin:

    import Component, { mixins } from 'vue-class-component'
    import MyMixin from './mixin.js'
     
    // Use `mixins` helper function instead of `Vue`.
    // `mixins` can receive any number of arguments.
    @Component
    export class MyComp extends mixins(MyMixin) {
      created () {
        console.log(this.mixinValue) // -> Hello
      }
    }

    Create Custom Decorators

    You can extend the functionality of this library by creating your own decorators. vue-class-component provides createDecorator helper to create custom decorators. createDecorator expects a callback function as the 1st argument and the callback will receive following arguments:

    • options: Vue component options object. Changes for this object will affect the provided component.
    • key: The property or method key that the decorator is applied.
    • parameterIndex: The index of a decorated argument if the custom decorator is used for an argument.

    Example of creating NoCache decorator:

    // decorators.js
    import { createDecorator } from 'vue-class-component'
     
    export const NoCache = createDecorator((options, key) => {
      // component options should be passed to the callback
      // and update for the options object affect the component
      options.computed[key].cache = false
    })
    import { NoCache } from './decorators'
     
    @Component
    class MyComp extends Vue {
      // the computed property will not be cached
      @NoCache
      get random () {
        return Math.random()
      }
    }

    Adding Custom Hooks

    If you use some Vue plugins like Vue Router, you may want class components to resolve hooks that they provides. For that case, Component.registerHooks allows you to register such hooks:

    // class-component-hooks.js
    import Component from 'vue-class-component'
     
    // Register the router hooks with their names
    Component.registerHooks([
      'beforeRouteEnter',
      'beforeRouteLeave',
      'beforeRouteUpdate' // for vue-router 2.2+
    ])
    // MyComp.js
    import Vue from 'vue'
    import Component from 'vue-class-component'
     
    @Component
    class MyComp extends Vue {
      // The class component now treats beforeRouteEnter
      // and beforeRouteLeave as Vue Router hooks
      beforeRouteEnter () {
        console.log('beforeRouteEnter')
      }
     
      beforeRouteLeave () {
        console.log('beforeRouteLeave')
      }
    }

    Note that you have to register the hooks before component definition.

    // main.js
     
    // Make sure to register before importing any components
    import './class-component-hooks'
     
    import Vue from 'vue'
    import MyComp from './MyComp'
     
    new Vue({
      el: '#app',
      components: {
        MyComp
      }
    })

    Caveats of Class Properties

    vue-class-component collects class properties as Vue instance data by instantiating the original constructor under the hood. While we can define instance data like native class manner, we sometimes need to know how it works.

    this value in property

    If you define an arrow function as a class property and access this in it, it will not work. This is because this is just a proxy object to Vue instance when initializing class properties:

    @Component
    class MyComp extends Vue {
      foo = 123
     
      bar = () => {
        // Does not update the expected property.
        // `this` value is not a Vue instance in fact.
        this.foo = 456
      }
    }

    You can simply define a method instead of a class property in that case because Vue will bind the instance automatically:

    @Component
    class MyComp extends Vue {
      foo = 123
     
      bar () {
        // Correctly update the expected property.
        this.foo = 456
      }
    }

    undefined will not be reactive

    To take consistency between the decorator behavior of Babel and TypeScript, vue-class-component does not make a property reactive if it has undefined as initial value. You should use null as initial value or use data hook to initialize undefined property instead.

    @Component
    class MyComp extends Vue {
      // Will not be reactive
      foo = undefined
     
      // Will be reactive
      bar = null
     
      data () {
        return {
          // Will be reactive
          baz: undefined
        }
      }
    }

    Build the Example

    $ npm install && npm run example

    Questions

    For questions and support please use the the official forum or community chat. The issue list of this repo is exclusively for bug reports and feature requests.

    License

    MIT

    install

    npm i vue-class-component

    Downloadsweekly downloads

    31,180

    version

    6.2.0

    license

    MIT

    repository

    githubgithub

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