一文秒懂vue-property-decorator

参考:https://github.com/kaorun343/vue-property-decorator 
怎么使vue支持ts写法呢,我们需要用到vue-property-decorator,这个组件完全依赖于vue-class-component.

首先安装:    npm i -D vue-property-decorator

我们来看下页面上代码展示:

<template>
  <div>
    foo:{{foo}}
    defaultArg:{{defaultArg}} | {{countplus}}
    <button @click="delToCount($event)">点击del emit</button>
    <HellowWordComponent></HellowWordComponent>
    <button ref="aButton">ref</button>
  </div>
</template>
 
<script lang="ts">
import { Component,Vue,Prop,Emit,Ref } from 'vue-property-decorator';
import HellowWordComponent from '@/components/HellowWordComponent.vue';
 
@Component({
  components: {
    HellowWordComponent,},beforeRouteLeave(to: any,from: any,next: any) {
    console.log('beforeRouteLeave');
    next();
  },beforeRouteEnter(to: any,})
 
export default class DemoComponent extends Vue {
  private foo = 'App Foo!';
 
  private count: number = this.$store.state.count;
 
  @Prop(Boolean) private defaultArg: string | undefined;
 
  @Emit('delemit') private delEmitClick(event: MouseEvent) {}
 
  @Ref('aButton') readonly ref!: HTMLButtonElement;
 
  // computed;
  get countplus () {
    return this.count;
  }
 
  created() {}
 
  mounted() {}
 
  beforeDestroy() {}
 
  public delToCount(event: MouseEvent) {
    this.delEmitClick(event);
    this.count += 1; // countplus 会累加
  }
 
}
 
</script>
 
<style lang="less">
...
</style>

vue-proporty-decorator它具备以下几个装饰器和功能:

• @Component
• @Prop
• @PropSync
• @Model
• @Watch
• @Provide
• @Inject
• @ProvideReactive
• @InjectReactive
• @Emit
• @Ref

1.@Component(options:ComponentOptions = {})

@Component 装饰器可以接收一个对象作为参数，可以在对象中声明 components ，filters，directives等未提供装饰器的选项，也可以声明computed，watch等

   registerHooks:
   除了上面介绍的将beforeRouteLeave放在Component中之外,还可以全局注册,就是registerHooks

<script lang="ts">
import { Component,Vue } from 'vue-property-decorator';
 
Component.registerHooks([
  'beforeRouteLeave','beforeRouteEnter',]);
 
@Component
export default class App extends Vue {
  beforeRouteLeave(to: any,next: any) {
    console.log('beforeRouteLeave');
    next();
  }
 
  beforeRouteEnter(to: any,next: any) {
    console.log('beforeRouteLeave');
    next();
  }
}
</script>

2.@Prop(options: (PropOptions | Constructor[] | Constructor) = {})

@Prop装饰器接收一个参数，这个参数可以有三种写法：

• Constructor，例如String，Number，Boolean等，指定 prop 的类型；
• Constructor[]，指定 prop 的可选类型；
• PropOptions，可以使用以下选项：type，default，required，validator。

注意:属性的ts类型后面需要加上undefined类型；或者在属性名后面加上!，表示非null 和 非undefined
的断言，否则编译器会给出错误提示；

// 父组件:
<template>
  <div class="Props">
    <PropComponent :name="name" :age="age" :sex="sex"></PropComponent>
  </div>
</template>
 
<script lang="ts">
import {Component,} from 'vue-property-decorator';
import PropComponent from '@/components/PropComponent.vue';
 
@Component({
  components: {PropComponent,})
export default class PropsPage extends Vue {
  private name = '张三';
  private age = 1;
  private sex = 'nan';
}
</script>
 
// 子组件:
<template>
  <div class="hello">
    name: {{name}} | age: {{age}} | sex: {{sex}}
  </div>
</template>
 
<script lang="ts">
import {Component,Prop} from 'vue-property-decorator';
 
@Component
export default class PropComponent extends Vue {
   @Prop(String) readonly name!: string | undefined;
   @Prop({ default: 30,type: Number }) private age!: number;
   @Prop([String,Boolean]) private sex!: string | boolean;
}
</script>

3，@PropSync(propName: string,options: (PropOptions | Constructor[] | Constructor) = {})

@PropSync装饰器与@prop用法类似，二者的区别在于：

• @PropSync 装饰器接收两个参数：

propName: string 表示父组件传递过来的属性名；

• options: Constructor | Constructor[] | PropOptions 与@Prop的第一个参数一致；@PropSync 会生成一个新的计算属性。

注意,使用PropSync的时候是要在父组件配合.sync使用的

// 父组件
<template>
  <div class="PropSync">
    <h1>父组件</h1>
    like:{{like}}
    <hr/>
    <PropSyncComponent :like.sync="like"></PropSyncComponent>
  </div>
</template>
 
<script lang='ts'>
import { Vue,Component } from 'vue-property-decorator';
import PropSyncComponent from '@/components/PropSyncComponent.vue';
 
@Component({components: { PropSyncComponent },})
export default class PropSyncPage extends Vue {
  private like = '父组件的like';
}
</script>
 
// 子组件
<template>
  <div class="hello">
    <h1>子组件:</h1>
    <h2>syncedlike:{{ syncedlike }}</h2>
    <button @click="editLike()">修改like</button>
  </div>
</template>
 
<script lang="ts">
import { Component,PropSync,} from 'vue-property-decorator';
 
@Component
export default class PropSyncComponent extends Vue {
  @PropSync('like',{ type: String }) syncedlike!: string; // 用来实现组件的双向绑定,子组件可以更改父组件穿过来的值
 
  editLike(): void {
    this.syncedlike = '子组件修改过后的syncedlike!'; // 双向绑定,更改syncedlike会更改父组件的like
  }
}
</script>

4.@Model(event?: string,options: (PropOptions | Constructor[] | Constructor) = {})

@Model装饰器允许我们在一个组件上自定义v-model，接收两个参数：

• event: string 事件名。
• options: Constructor | Constructor[] | PropOptions 与@Prop的第一个参数一致。

注意,有看不懂的,可以去看下vue官网文档, https://cn.vuejs.org/v2/api/#model

// 父组件
<template>
  <div class="Model">
    <ModelComponent v-model="fooTs" value="some value"></ModelComponent>
    <div>父组件 app : {{fooTs}}</div>
  </div>
</template>
<script lang="ts">
import { Component,Vue } from 'vue-property-decorator';
import ModelComponent from '@/components/ModelComponent.vue';
 
@Component({ components: {ModelComponent} })
export default class ModelPage extends Vue {
  private fooTs = 'App Foo!';
}
</script>
 
// 子组件
<template>
  <div class="hello">
    子组件:<input type="text" :value="checked" @input="inputHandle($event)"/>
  </div>
</template>
 
<script lang="ts">
import {Component,Model,} from 'vue-property-decorator';
 
@Component
export default class ModelComponent extends Vue {
   @Model('change',{ type: String }) readonly checked!: string
 
   public inputHandle(that: any): void {
     this.$emit('change',that.target.value); // 后面会讲到@Emit,此处就先使用this.$emit代替
   }
}
</script>

5，@Watch(path: string,options: WatchOptions = {})

• @Watch 装饰器接收两个参数：
• path: string 被侦听的属性名；options?: WatchOptions={} options可以包含两个属性 ：

immediate?:boolean 侦听开始之后是否立即调用该回调函数；
deep?:boolean 被侦听的对象的属性被改变时，是否调用该回调函数；

发生在beforeCreate勾子之后，created勾子之前

<template>
  <div class="PropSync">
    <h1>child:{{child}}</h1>
    <input type="text" v-model="child"/>
  </div>
</template>
 
<script lang="ts">
import { Vue,Watch,Component } from 'vue-property-decorator';
 
@Component
export default class WatchPage extends Vue {
  private child = '';
 
  @Watch('child')
  onChildChanged(newValue: string,oldValue: string) {
    console.log(newValue);
    console.log(oldValue);
  }
}
</script>

6，@Emit(event?: string)

• @Emit 装饰器接收一个可选参数，该参数是$Emit的第一个参数，充当事件名。如果没有提供这个参数，$Emit会将回调函数名的camelCase转为kebab-case，并将其作为事件名；
• @Emit会将回调函数的返回值作为第二个参数，如果返回值是一个Promise对象，$emit会在Promise对象被标记为resolved之后触发；
• @Emit的回调函数的参数，会放在其返回值之后，一起被$emit当做参数使用。

// 父组件
<template>
  <div class="">
    点击emit获取子组件的名字<br/>
    姓名:{{emitData.name}}
    <hr/>
    <EmitComponent sex='女' @add-to-count="returnPersons" @delemit="delemit"></EmitComponent>
  </div>
</template>
 
<script lang="ts">
import { Vue,Component } from 'vue-property-decorator';
import EmitComponent from '@/components/EmitComponent.vue';
 
@Component({
  components: { EmitComponent },})
export default class EmitPage extends Vue {
  private emitData = { name: '我还没有名字' };
 
  returnPersons(data: any) {
    this.emitData = data;
  }
 
  delemit(event: MouseEvent) {
    console.log(this.emitData);
    console.log(event);
  }
}
</script>
 
// 子组件
<template>
  <div class="hello">
    子组件:
    <div v-if="person">
      姓名:{{person.name}}<br/>
      年龄:{{person.age}}<br/>
      性别:{{person.sex}}<br/>
    </div>
    <button @click="addToCount(person)">点击emit</button>
    <button @click="delToCount($event)">点击del emit</button>
  </div>
</template>
 
<script lang="ts">
import {
  Component,} from 'vue-property-decorator';
 
type Person = {name: string; age: number; sex: string };
 
@Component
export default class PropComponent extends Vue {
  private name: string | undefined;
 
  private age: number | undefined;
 
  private person: Person = { name: '我是子组件的张三',age: 1,sex: '男' };
 
  @Prop(String) readonly sex: string | undefined;
 
  @Emit('delemit') private delEmitClick(event: MouseEvent) {}
 
  @Emit() // 如果此处不设置别名字,则默认使用下面的函数命名
  addToCount(p: Person) { // 此处命名如果有大写字母则需要用横线隔开  @add-to-count
    return this.person; // 此处不return,则会默认使用括号里的参数p;
  }
 
  delToCount(event: MouseEvent) {
    this.delEmitClick(event);
  }
}
</script>

7，@Ref(refKey?: string)

@Ref 装饰器接收一个可选参数，用来指向元素或子组件的引用信息。如果没有提供这个参数，会使用装饰器后面的属性名充当参数

<template>
  <div class="PropSync">
    <button @click="getRef()" ref="aButton">获取ref</button>
    <RefComponent name="names" ref="RefComponent"></RefComponent>
  </div>
</template>
 
<script lang="ts">
import { Vue,Component,Ref } from 'vue-property-decorator';
import RefComponent from '@/components/RefComponent.vue';
 
@Component({
  components: { RefComponent },})
export default class RefPage extends Vue {
  @Ref('RefComponent') readonly RefC!: RefComponent;
  @Ref('aButton') readonly ref!: HTMLButtonElement;
  getRef() {
    console.log(this.RefC);
    console.log(this.ref);
  }
}
</script>

8.Provide/Inject   ProvideReactive/InjectReactive

@Provide(key?: string | symbol) / @Inject(options?: { from?: InjectKey,default?: any } | InjectKey) decorator @ProvideReactive(key?: string | symbol) / @InjectReactive(options?: { from?: InjectKey,default?: any } | InjectKey) decorator

提供/注入装饰器,
key可以为string或者symbol类型,

相同点:Provide/ProvideReactive提供的数据,在内部组件使用Inject/InjectReactive都可取到
不同点:
如果提供(ProvideReactive)的值被父组件修改，则子组件可以使用InjectReactive捕获此修改。

// 最外层组件
<template>
  <div class="">
    <H3>ProvideInjectPage页面</H3>
    <div>
      在ProvideInjectPage页面使用Provide,ProvideReactive定义数据,不需要props传递数据
      然后爷爷套父母,父母套儿子,儿子套孙子,最后在孙子组件里面获取ProvideInjectPage
      里面的信息
    </div>
    <hr/>
    <provideGrandpa></provideGrandpa> <!--爷爷组件-->
  </div>
</template>
 
<script lang="ts">
import {
  Vue,Provide,ProvideReactive,} from 'vue-property-decorator';
import provideGrandpa from '@/components/ProvideGParentComponent.vue';
 
@Component({
  components: { provideGrandpa },})
export default class ProvideInjectPage extends Vue {
  @Provide() foo = Symbol('fooaaa');
 
  @ProvideReactive() fooReactive = 'fooReactive';
 
  @ProvideReactive('1') fooReactiveKey1 = 'fooReactiveKey1';
 
  @ProvideReactive('2') fooReactiveKey2 = 'fooReactiveKey2';
 
  created() {
    this.foo = Symbol('fooaaa111');
    this.fooReactive = 'fooReactive111';
    this.fooReactiveKey1 = 'fooReactiveKey111';
    this.fooReactiveKey2 = 'fooReactiveKey222';
  }
}
</script>
 
// ...provideGrandpa调用父母组件
<template>
  <div class="hello">
    <ProvideParentComponent></ProvideParentComponent>
  </div>
</template>
 
// ...ProvideParentComponent调用儿子组件
<template>
  <div class="hello">
    <ProvideSonComponent></ProvideSonComponent>
  </div>
</template>
 
// ...ProvideSonComponent调用孙子组件
<template>
  <div class="hello">
    <ProvideGSonComponent></ProvideGSonComponent>
  </div>
</template>
 
 
// 孙子组件<ProvideGSonComponent>,经过多层引用后,在孙子组件使用Inject可以得到最外层组件provide的数据哦
<template>
  <div class="hello">
    <h3>孙子的组件</h3>
    爷爷组件里面的foo:{{foo.description}}<br/>
    爷爷组件里面的fooReactive:{{fooReactive}}<br/>
    爷爷组件里面的fooReactiveKey1:{{fooReactiveKey1}}<br/>
    爷爷组件里面的fooReactiveKey2:{{fooReactiveKey2}}
    <span style="padding-left:30px;">=> fooReactiveKey2没有些key所以取不到哦</span>
  </div>
</template>
 
<script lang="ts">
import {
  Component,Inject,InjectReactive,} from 'vue-property-decorator';
 
@Component
export default class ProvideGSonComponent extends Vue {
  @Inject() readonly foo!: string;
 
  @InjectReactive() fooReactive!: string;
 
  @InjectReactive('1') fooReactiveKey1!: string;
 
  @InjectReactive() fooReactiveKey2!: string;
}
</script>

demo地址:https://github.com/slailcp/vue-cli3/tree/master/src/pc-project/views/manage

原文地址：https://blog.csdn.net/sllailcp/article/details/102542796