Vue.js属性装饰器库vue-property-decorator文档

英文原文: https://github.com/kaorun343/vue-property-decorator/blob/master/README.md

此库完全依赖于vue-class-component, 所以请使用此库前, 先阅读它的文档

安装

npm i -S vue-property-decorator

使用

这是一些装饰器和一个Mixin函数

@Prop
@PropSync
@Model
@Watch
@Provide
@Inject
@ProvideReactive
@InjectReactive
@Emit
@Ref
@Component (由 vue-class-component提供)
Mixins (名为mixins的辅助函数, 由 vue-class-component提供)

查看Vuex的库

vuex-class

@Prop(options: (PropOptions | Constructor[] | Constructor) = {}) 装饰器

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
}

相当于

export default {
  props: {
    propA: {
      type: Number
    },
    propB: {
      default: 'default value'
    },
    propC: {
      type: [String, Boolean]
    }
  }
}

笔记:

如果你想要获取类型定义来设置每个prop值的`type`属性, 你可以使用 reflect-metadata.

将 emitDecoratorMetadata 设置为 true.
在引入vue-property-decorator 之前引入 reflect-metadata (只需引入一次 reflect-metadata.)

import 'reflect-metadata'
import { Vue, Component, Prop } from 'vue-property-decorator'

@Component
export default class MyComponent extends Vue {
  @Prop() age!: number
}

每个prop的默认值都要定义为与上面示例代码相同

不再支持像@Prop() prop = 'default value' 这样定义每个默认属性 .

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

import { Vue, Component, PropSync } from 'vue-property-decorator'

@Component
export default class YourComponent extends Vue {
  @PropSync('name', { type: String }) syncedName!: string
}

is equivalent to

export default {
  props: {
    name: {
      type: String
    }
  },
  computed: {
    syncedName: {
      get() {
        return this.name
      },
      set(value) {
        this.$emit('update:name', value)
      }
    }
  }
}

除此之外, 它就像除了将prop名称作为修饰器参数外的 @Prop, 此外它还在后面创建了一个计算属性的 getter 和 setter. 这样你可以将它作为常规数据属性来与这个属性进行交互, 同时也使交互和在父组件上添加.sync一样容易.

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

import { Vue, Component, Model } from 'vue-property-decorator'

@Component
export default class YourComponent extends Vue {
  @Model('change', { type: Boolean }) readonly checked!: boolean
}

等价于

export default {
  model: {
    prop: 'checked',
    event: 'change'
  },
    prop: 'checked',
    event: 'change'
  props: {
    checked: {
      type: Boolean
    }
  }
}

@Model 属性也可以通过reflect-metadata获取类型定义来设置type属性.

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

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) {}
}

等价于

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) {}
  }
}

@Provide(key?: string | symbol)`/`@Inject(options?: { from?: InjectKey, default?: any } | InjectKey) 装饰器

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'
}

等价于

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
    }
  }
})

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

这两个修饰器是@Provide 和 @Inject 的响应式版本. 如果一个被提供的值被父组件修改, 子组件可以监听到这个修改.

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
}

@Emit(event?: string) 装饰器

@Emit $emit 装饰的函数, 它们的返回值后面跟着它们的原始参数. 如果返回值是一个Promise对象, 则会在触发前达到完成状态.

如果事件名称不提供 event 参数, 函数名将会被代替使用. 在这种情况下, 驼峰命名将被转换成短横线隔开式命名.

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)
    })
  }
}

等价于

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)
      })
    }
  }
}

@Ref(refKey?: string) 装饰器

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
}

等价于

export default {
  computed() {
    anotherComponent: {
      cache: false,
      get() {
        return this.$refs.anotherComponent as AnotherComponent
      }
    },
    button: {
      cache: false,
      get() {
        return this.$refs.aButton as HTMLButtonElement
      }
    }
  }
}