vue2 + ts 之基础语法

定义数据 与插值表达式

<!-- -->
<template>
  <div>
    MenuBar
    {{ msg }}
    <div v-for="item in arr" :key="item">
      {{ item }}
    </div>
  </div>
</template>

<script lang="ts">
import { Component, Vue, Watch } from 'vue-property-decorator'
@Component({
  components: {}
})
export default class MenuBar extends Vue {
  msg = '我是msg'
  arr = [1, 2, 3]
}
</script>
<style scoped></style>

修改 data数据

<!-- -->
<template>
  <div>
    <div>
      count - {{count}} 
      <button @click="addCount">修改count</button>
    </div>
  </div>
</template>

<script lang="ts">
import { Component, Vue, Watch } from 'vue-property-decorator'
@Component({
  components: {}
})
export default class MenuBar extends Vue {
  private count:number = 0
  private addCount(){
    this.count++
  }
}
</script>
<style scoped></style>

定义事件

<!-- -->
<template>
  <div>
    MenuBar
    {{ msg }}
    <div v-for="item in arr" :key="item">
      {{ item }}
    </div>
    <button @click="clickBtn">修改最后一项</button>
  </div>
</template>

<script lang="ts">
import { Component, Vue, Watch } from 'vue-property-decorator'
@Component({
  components: {}
})
export default class MenuBar extends Vue {
  private msg = '我是msg'
  private arr = [1, 2, 3]
  private clickBtn() {
    // this.arr[2] = 333 // 直接修改下标 数据修改了 但是视图不修改
    // console.log('this.arr', this.arr) // 修改数组下标的值 不会影响视图 [1, 2, 333]
    this.$set(this.arr, 0, 111)
    console.log('this.arr', this.arr) // 修改数组下标的值 不会影响视图 [111, 2, 333]
  }
}
</script>
<style scoped></style>

v-model 与 计算属性

<!-- -->
<template>
  <div>
    MenuBar
    {{ msg }}
    <input type="text" v-model="msg" />
  </div>
</template>

<script lang="ts">
import { Component, Vue} from 'vue-property-decorator'
@Component({
  components: {}
})
export default class MenuBar extends Vue {
  msg = '我是msg'
  // 计算属性
  get getMsg(): string {
    return this.msg + ' - 计算属性'
  }
  set getMsg(val) {
    console.log("val",val);
  }
}
</script>
<style scoped></style>

v-model 与 watch

监听简单数据类型

<!-- -->
<template>
  <div>
    {{ msg }}
    <input type="text" v-model="msg" />
  </div>
</template>

<script lang="ts">
import { Component, Vue, Watch } from 'vue-property-decorator'
@Component({
  components: {}
})
export default class MenuBar extends Vue {
  msg: string = '我是msg'
  //  监听器
  @Watch('msg')
  onMsgChanged(newV: any, oldVal: any) {
    console.log('newV', newV)
  }
}
</script>
<style scoped></style>

监听对象

<!-- -->
<template>
  <div>
    <div>
      - person {{ person }}
      <button @click="changePerson">changePerson</button>
    </div>
  </div>
</template>

<script lang="ts">
import { Component, Vue, Watch } from 'vue-property-decorator'
type Person = {
  name: string
}
@Component({
  components: {}
})
export default class MenuBar extends Vue {
  private count: number = 1
  person: Person = {
    name: 'ppp'
  }
  private changePerson() {
    this.person.name = 'ooo'
  }
  // 监听对象的属性
  @Watch('person.name', { immediate: true, deep: true })
  onPersonChange(newVal: any, oldVal: any) {
    console.log(newVal + ',' + oldVal) // ooo , ppp
  }
  // 监听对象的属性
  @Watch('person', { immediate: true, deep: true })
  onPersonObjChange(newVal: any, oldVal: any) {
    console.log(newVal, oldVal) // { name: 'ooo'} { name: 'ooo'}
  }
}
</script>
<style scoped></style>

prop 与 Emit

子组件

<!-- -->
<template>
  <div>
    MenuBar
    <div>父组件的msg - {{ msg }}</div>
    <button @click="changeMsg">子组件 修改 父组件的msg</button>
  </div>
</template>

<script lang="ts">
import { Component, Prop, Vue, Emit } from 'vue-property-decorator'
@Component({
  components: {}
})
export default class MenuBar extends Vue {
  @Prop(String) private msg!: string

  // Emit子组件触发
  @Emit('changeMsg')
  private changeMsg(val: number) {
    return '我是子组件修改后的msg'
  }
}
</script>
<style lang="scss" scoped></style>

父组件

<template>
  <div id="app">
    <MenuBar :msg="msg" @changeMsg="changeMsg"></MenuBar>
  </div>
</template>

<script lang="ts">
import { Component, Vue, Watch } from 'vue-property-decorator'
import MenuBar from '@/components/MenuBar.vue'

@Component({
  components: {
    MenuBar
  }
})
export default class App extends Vue {
  private msg: string = 'msg信息'

  @Watch('msg')
  onChangeMsg(val: any, oldVal: any) {
    console.log('val', val, 'oldVal', oldVal)
  }
  private changeMsg(val): void {
    console.log('changeMsg', val)
    this.msg = val
  }
}
</script>

<style>
#app {
  width: 100%;
  height: 100%;
  background: #e5e5e5;
}
</style>

• 效果
  
  

生命周期函数

<!-- -->
<template>
  <div>count - {{ count }}</div>
</template>

<script lang="ts">
import { Component, Vue, Watch } from 'vue-property-decorator'
@Component({
  components: {}
})
export default class MenuBar extends Vue {
  private count: number = 0
  // 生命周期
  private created() {
    this.count = 2
    console.log("created",this.count); // created 2
    
  }
  private mounted() {
    this.count = 3
    console.log("mounted",this.count); // mounted 3
  }
}
</script>
<style scoped></style>

Ref的使用

<!-- -->
<template>
  <div>
    <div class="header" ref="header" id="ID">我是头部啊</div>
    <Demo1 ref="demo1Ref"></Demo1>
  </div>
</template>

<script lang="ts">
import { Component, Ref, Vue, Watch } from 'vue-property-decorator'
@Component({
  components: {}
})
export default class MenuBar extends Vue {
// 方式1
  @Ref('header') readonly headerRef!: HTMLDivElement
  private mounted() {
    console.log('headerRef', this.headerRef.id) // 获取dom节点的 id值 headerRef ID
  }
// 方式2
$ref!:{  demo1Ref: Demo1 }
mounted ( ) { console.log('ref', this.$refs.demo1Ref.add(1, 2)) // ref 3 }
}
</script>
<style scoped></style>