vue 组件通信

Posted 2023-03-26 小阁下的 BLOG

1. 子组件间通信(defineEmits + defineProps)

1.1 实现效果

在一个子组件的输入框中输入数据, 在另一个子组件上显示. 如下图:

1.2 defineEmits 和 defineProps 的 TS 使用

1.2.1 defineEmits 的 TS 使用

export declare function defineEmits<TypeEmit>(): TypeEmit;

// 根据上面的定义, 我们可以知道通过传入函数签名可以为其返回的 emit 方法定义类型, 对 emit 进行精确的类型定义
const emit = defineEmits<
  (e: \'update-age\', data: number): void
  (e: \'update-name\', data: string): void
>()

1.2.2 defineProps 的 TS 使用

export declare function defineProps<TypeProps>(): Readonly<Omit<TypeProps, BooleanKey<TypeProps>> & 
    [K in keyof Pick<TypeProps, BooleanKey<TypeProps>>]-?: NotUndefined<TypeProps[K]>;
>;

/**
  * defineProps<
  *   propName1: TSType,
  *   propName2: TSType,
  *   ......
  * >()
  */

1.2.2.1 另外两种 JS 使用

export declare function defineProps<PropNames extends string = string>(props: PropNames[]): Readonly<
    [key in PropNames]?: any;
>;
// defineProps([\'propName1\', \'propName2\', ...])

export declare function defineProps<PP extends ComponentObjectPropsOptions = ComponentObjectPropsOptions>(props: PP): Readonly<ExtractPropTypes<PP>>;

export declare type ComponentObjectPropsOptions<P = Data> = 
    [K in keyof P]: Prop<P[K]> | null;
;

export declare type Prop<T, D = T> = PropOptions<T, D> | PropType<T>;

declare interface PropOptions<T = any, D = T> 
    type?: PropType<T> | true | null;
    required?: boolean;
    default?: D | DefaultFactory<D> | null | undefined | object;
    validator?(value: unknown): boolean;


declare type Data = Record<string, unknown>;

/**
 * defineProps(
 *   propName1: 
 *     type: propName1Type,
 *     required: isRequired,
 *     default: defaultValue
 *   ,
 *   propName2: propName2Type,
 *   ......
 * )
 */

1.3 具体实现

1.3.1 children-component-one

<!-- children-component-one --> 
<script setup lang="ts">
import  ref  from \'vue\'

const inputValue = ref(\'\')

const emit = defineEmits<
  (e: \'update-input-text\', data: string): void
>()

const handleInput = () => 
  emit(\'update-input-text\', inputValue.value)

</script>

<template>
  <div class="children-component-one">
    inputValue: <input type="text" v-model="inputValue" @input="handleInput" />
  </div>
</template>

1.3.2 children-component-two

<!-- children-component-two -->
<script setup lang="ts">
defineProps<
  inputTextValue: string
>()
</script>

<template>
  <div class="children-component-two">
    show:  inputTextValue 
  </div>
</template>

1.3.3 parent-component

<!-- app.vue -->
<script setup lang="ts">
import  ref  from \'vue\'
import childrenComponentOne from \'./views/children-component-one.vue\'
import childrenComponentTwo from \'./views/children-component-two.vue\'

const inputText = ref(\'\')

const inputTextUpdateHandle = (newValue: string) => 
  inputText.value = newValue

</script>

<template>
  <div class="app">
    <h2>app</h2>
    <children-component-one @update-input-text="inputTextUpdateHandle"/>
    <children-component-two :input-text-value="inputText" /> <!-- 父组件向子组件传值 -->
  </div>
</template>

通过 defineEmits 可以实现子组件向父组件传值

通过 defineProps 可以实现子组件接收父组件传来的值

两者配合即可实现子组件间的通信

2. 父子组件间的通信(v-model + defineEmits + defineProps)

2.1 实现效果

父组件有一计数器 counter , 子组件有一 button , 通过点击 button 可以使得 counter + 1 , 而 counter 的显示则交由父组件

2.2 具体实现

2.2.1 children-component

<script setup lang="ts">
const props = defineProps<
  counter: number
>()

const emit = defineEmits<
  (e: \'update:counter\', data: number): void
>()

const handleClick = () => 
  emit(\'update:counter\', props.counter + 1)

</script>

<template>
  <div class="children-component">
    <h2>children-component</h2>
    <button @click="handleClick">add one</button>
  </div>
</template>

2.2.2 parent-component

<script setup lang="ts">
import  ref  from \'vue\'
import childrenComponent from \'../children-component/children-component.vue\'

const counter = ref(0)
</script>

<template>
  <div class="parent-component">
    <h2>parent-component</h2>
    Counter:  counter 
    <children-component v-model:counter="counter" />
  </div>
</template>

3. 父子组件间的通信(ref + defineExpose)

3.1 实现效果

子组件中有一计数器 counter 和一个能令 counter + 1 的 button , 且子组件将传递 counter 给父组件, 由父组件来进行展示. 如下图所示:

3.2 defineExpose 的 TS 使用

declare function defineExpose<Exposed extends Record<string, any> = Record<string, any>>(exposed?: Exposed): void;

/**
 * const passValue: PassType = someValue
 * defineExpose(passValue)
 */

3.3 具体实现

3.3.1 parent-component

<script setup lang="ts">
import  ref, type Ref  from \'vue\'
import childrenComponent from \'../children-component/children-component.vue\'
import type  PassType  from \'@/types\'

const passValue = ref() as Ref<PassType>
</script>

<template>
  <div class="parent-component">
    <h2>parent-component</h2>
    Counter:  passValue.counter 
    <children-component ref="passValue" />
  </div>
</template>

3.3.2 children-component

<script setup lang="ts">
import  ref  from \'vue\'
import type  PassType  from \'@/types\';

const counter = ref(0)

const handleClick = () => 
  counter.value++


const passValue: PassType =  counter 

defineExpose(passValue)
</script>

<template>
  <div class="children-component">
    <h2>children-component</h2>
    <button @click="handleClick">add one</button>
  </div>
</template>

3.3.3 src/types/index.ts

export interface PassType 
  counter: Ref<number>

4. 祖先-后代组件间的通信(Provide + Inject)

由祖先节点通过 Provide 提供需要传递的值, 而该节点的任何后代节点都可以通过 Inject 接收传递的值

4.1 实现效果

祖先组件拥有一个 counter 和一个可以令 counter + 1 的 button, 并将 counter 传递给后代组件, 交由后代组件来进行展示

4.2 Provide + Inject 的 TS 使用

declare function provide<T>(key: InjectionKey<T> | string | number, value: T): void

declare function inject<T>(key: InjectionKey<T> | string): T | undefined

export declare interface InjectionKey<T> extends Symbol 
// 由这行代码可知: InjectionKey<T> 类型可以接收 Symbol 类型的值

// 由上面的代码块可知
// 用法 1 :
const value: ValueType = someValue
const key: InjectionKey<ValueType> = Symbol(\'key-name\')

provide(key, value)
const passValue: ValueType = inject(key)

// 用法 2:
const value: ValueType = someValue

provide(\'pass-value\', value)
const passValue = inject<ValueType>(\'pass-value\')

4.3 具体实现

4.3.1 src/types/index.ts

import type  InjectionKey, Ref  from \'vue\'

export type CounterType = Ref<number>
export const key: InjectionKey<CounterType> = Symbol(\'CounterType\')

4.3.2 祖先组件

<script setup lang="ts">
import  key  from \'@/types\';
import  provide, ref  from \'vue\'
import childrenComponent from \'../children-component/children-component.vue\'

const counter = ref(0)
const handleClick = () => 
  counter.value++


provide(key, counter)
</script>

<template>
  <div class="parent-component">
    <h2>parent-component</h2>
    <button @click="handleClick">add one</button>
    <children-component />
  </div>
</template>

4.3.3 后代组件

<script setup lang="ts">
import  inject  from \'vue\'
import  key  from \'@/types/index\'

const counter = inject(key)
</script>

<template>
  <div class="children-component">
    <h2>children-component</h2>
    Counter:  counter 
  </div>
</template>

5. 状态管理工具(Pinia / Vuex)