vue-property-decorator
本文翻譯自 vue-property-decorator
這個庫徹底依賴 vue-class-component 庫棉胀，請在使用這個庫之前先閱讀它的 readme
安裝
npm i -S vue-property-decorator
用法
這里有一些修飾器（decorators）以及一個函數(shù)（Mixin）
@Prop
@PropSync
@Model
@Watch
@Provide
@Inject
@ProvideReactive
@InjectReactive
@Emit
@Ref
@Component (由 vue-class-component 提供)
Mixins (幫助函數(shù) mixins 由 vue-class-component 提供)
另請查閱
(vuex-class)[https://github.com/ktsn/vuex-class/]
<a id="Prop"></a> @Prop(options: (PropOptions | Constructor[] | Constructor) = {})修飾器
import { Vue, Component, Prop } from 'vue-property-decorator'
@Component
export default class YourComponent extends Vue {
@Prop(Number) readonly propA: number | undefined
@Prop({ default: 'default value' }) readonly propB!: string
@Prop([String, Boolean]) readonly propC: string | boolean | undefined
}
等同于
export default {
props: {
propA: {
type: Number
},
propB: {
default: 'default value'
},
propC: {
type: [String, Boolean]
}
}
}
注意：
如果你想要通過 type 設置給每個 prop 值設置 type 屬性，你可以使用 reflect-metadata
1.設置 emitDecoratorMetadata 為 true
2.在引入 vue-property-decorator 之前引入 reflect-metadata（只需要引入一次）
import 'reflect-metadata'
import { Vue, Component, Prop } from 'vue-property-decorator'
@Component
export default class MyComponent extends Vue {
@Prop() age!: number
}
每個 prop 的默認值必須向上面這樣定義
不支持像這樣定義默認值：@Prop() prop = 'default value'
<a id="PropSync"></a> @PropSync(propName: string, options: (PropOptions | Constructor[] | Constructor) = {}) decorator
import { Vue, Component, PropSync } from 'vue-property-decorator'
@Component
export default class YourComponent extends Vue {
@PropSync('name', { type: String }) syncedName!: string
}
等同于：
export default {
props: {
name: {
type: String
}
},
computed: {
syncedName: {
get() {
return this.name
},
set(value) {
this.$emit('update:name', value)
}
}
}
}
不同于僅僅像 @Prop 一樣工作召廷，也不同于僅僅是把 propName 當做修飾器的參數(shù)绵患，它還自動進一步幫我們創(chuàng)建了一個計算屬性的 getter 和 setter雾叭，通過這樣的方式，你可以像 data 屬性一樣使用這個屬性藏雏，與此同時拷况，我們只需要在父組件添加 .sync 修飾符
<a id="Model"></a> @Model(event?: string, options: (PropOptions | Constructor[] | Constructor) = {}) decorator
import { Vue, Component, Model } from 'vue-property-decorator'
@Component
export default class YourComponent extends Vue {
@Model('change', { type: Boolean }) readonly checked!: boolean
}
等同于：
export default {
model: {
prop: 'checked',
event: 'change'
},
props: {
checked: {
type: Boolean
}
}
}
@Model 屬性也可以通過 reflect-metadata 來設置默認類型
<a id="Watch"></a> @Watch(path: string, options: WatchOptions = {}) decorator
import { Vue, Component, Watch } from 'vue-property-decorator'
@Component
export default class YourComponent extends Vue {
@Watch('child')
onChildChanged(val: string, oldVal: string) {}
@Watch('person', { immediate: true, deep: true })
onPersonChanged1(val: Person, oldVal: Person) {}
@Watch('person')
onPersonChanged2(val: Person, oldVal: Person) {}
}
等同于
export default {
watch: {
child: [
{
handler: 'onChildChanged',
immediate: false,
deep: false
}
],
person: [
{
handler: 'onPersonChanged1',
immediate: true,
deep: true
},
{
handler: 'onPersonChanged2',
immediate: false,
deep: false
}
]
},
methods: {
onChildChanged(val, oldVal) {},
onPersonChanged1(val, oldVal) {},
onPersonChanged2(val, oldVal) {}
}
}
<a id="Provide"></a><a id="Inject"></a> @Provide(key?: string | symbol) / @Inject(options?: { from?: InjectKey, default?: any } | InjectKey) decorator
import { Component, Inject, Provide, Vue } from 'vue-property-decorator'
const symbol = Symbol('baz')
@Component
export class MyComponent extends Vue {
@Inject() readonly foo!: string
@Inject('bar') readonly bar!: string
@Inject({ from: 'optional', default: 'default' }) readonly optional!: string
@Inject(symbol) readonly baz!: string
@Provide() foo = 'foo'
@Provide('bar') baz = 'bar'
}
等同于
const symbol = Symbol('baz')
export const MyComponent = Vue.extend({
inject: {
foo: 'foo',
bar: 'bar',
optional: { from: 'optional', default: 'default' },
[symbol]: symbol
},
data() {
return {
foo: 'foo',
baz: 'bar'
}
},
provide() {
return {
foo: this.foo,
bar: this.baz
}
}
})
<a id="ProvideReactive"></a><a id="InjectReactive"></a> @ProvideReactive(key?: string | symbol) / @InjectReactive(options?: { from?: InjectKey, default?: any } | InjectKey) decorator
這個是 @Provide和@Inject的響應式版本，如果一個提供（provide）的值在父組件修改了掘殴，子組件可以捕捉到這些更改
const key = Symbol()
@Component
class ParentComponent extends Vue {
@ProvideReactive() one = 'value'
@ProvideReactive(key) two = 'value'
}
@Component
class ChildComponent extends Vue {
@InjectReactive() one!: string
@InjectReactive(key) two!: string
}
<a id="Emit"></a> @Emit(event?: string) decorator
被 @Emit 修飾的函數(shù)赚瘦，會 $emit 它返回的值，以及它的參數(shù)（放在返回值后面）奏寨，如果返回的是一個 promise起意，會先 resolved 再觸發(fā)事件。
如果 @Emit 后面沒有跟著事件名作為參數(shù)病瞳，函數(shù)名會作為事件名稱揽咕，在這種情況下，駝峰式的名字會被改為短橫線隔開式（kebab-case）
import { Vue, Component, Emit } from 'vue-property-decorator'
@Component
export default class YourComponent extends Vue {
count = 0
@Emit()
addToCount(n: number) {
this.count += n
}
@Emit('reset')
resetCount() {
this.count = 0
}
@Emit()
returnValue() {
return 10
}
@Emit()
onInputChange(e) {
return e.target.value
}
@Emit()
promise() {
return new Promise(resolve => {
setTimeout(() => {
resolve(20)
}, 0)
})
}
}
等同于
export default {
data() {
return {
count: 0
}
},
methods: {
addToCount(n) {
this.count += n
this.$emit('add-to-count', n)
},
resetCount() {
this.count = 0
this.$emit('reset')
},
returnValue() {
this.$emit('return-value', 10)
},
onInputChange(e) {
this.$emit('on-input-change', e.target.value, e)
},
promise() {
const promise = new Promise(resolve => {
setTimeout(() => {
resolve(20)
}, 0)
})
promise.then(value => {
this.$emit('promise', value)
})
}
}
}
<a id="Ref"></a> @Ref(refKey?: string) decorator
import { Vue, Component, Ref } from 'vue-property-decorator'
import AnotherComponent from '@/path/to/another-component.vue'
@Component
export default class YourComponent extends Vue {
@Ref() readonly anotherComponent!: AnotherComponent
@Ref('aButton') readonly button!: HTMLButtonElement
}
等同于
export default {
computed() {
anotherComponent: {
cache: false,
get() {
return this.$refs.anotherComponent as AnotherComponent
}
},
button: {
cache: false,
get() {
return this.$refs.aButton as HTMLButtonElement
}
}
}
}
