vue3 状态管理工具 pinia 使用

1、安装pinia

npm install pinia --save

2、创建 Store

新建一个 store 文件，创建 index.ts

import { createPinia } from "pinia";
const store = createPinia();
export default store;

3、在main.ts里全局引入

import { createApp } from "vue";
import App from "./App.vue";
import router from "./router";
import store from "./store"; // 引入 
 
const app = createApp(App);
app.use(router);
app.use(store); // 注册
app.mount("#app");

4、定义一个store

在 store 文件里建一个 counter.ts ，定义该状态管理，可根据自己项目建多个

import { defineStore } from "pinia";
export const useCounterStore = defineStore("counter", {
  state: () => {   // 数据
    return { 
      count: 0,
      msg: "我cao",
      todoList: ["111", "222"],
    };
  },
  getters: {
    doubleCount(state: any): number {   // 计算
      return state.count * 2;
    },
  },
  actions: {
    increment(payload?: number) {   // 方法
      this.count = payload ? this.count + payload : this.count + 1;
    },
  },
});

5、访问State

<template>
  <div class="home">
    <p>{{ counterStore.msg }}</p>
    <p>{{ counterStore.count }}</p>
    <p>{{ counterStore.doubleCount }}</p>
    <ul>
      <li v-for="(item, index) in todoList" :key="index">{{ item }}</li>
    </ul>
  </div>
</template>
 
<script setup lang="ts">
 
import { useCounterStore } from "@/store/counter";  // 引入
 
const counterStore = useCounterStore();  // 使用
 
</script>

你也可以使用storeToRefs进行解构  

<template>
  <div class="about">
    <p>{{ count }}</p>
    <p>{{ msg }}</p>
    <p>{{ doubleCount }}</p>
    <ul>
      <li v-for="(item, index) in todoList" :key="index">{{ item }}</li>
    </ul>
  </div>
</template>
 
<script setup lang="ts">
  import { storeToRefs } from 'pinia'
  import { useCounterStore } from '@/stores/counter'
  const counterStore = useCounterStore()
  // 也可以使用storeToRefs进行解构
  let { count, doubleCount, msg, todoList } = storeToRefs(counterStore)
</script>

defineComponent 模式下的使用

<template>
  <div class="hello">
    <p>{{ counterStore.msg }}</p>
    <p>{{ counterStore.count }}</p>
    <p>{{ counterStore.doubleCount }}</p>
    <p>{{ counterStore }}.........</p>
 
    <p @click="test">直接修改</p>
  </div>
</template>
 
<script lang="ts">
import { defineComponent } from "vue";
import { useCounterStore } from "@/store/counter"; // 引入
export default defineComponent({
  name: "HelloWorld",
  props: {
    msg: String,
  },
  setup() {
    const counterStore = useCounterStore();  // 调用
 
    const test = () => {
      counterStore.count++; 
    };
    return {
      counterStore,  // 返回
      test,
    };
  },
});
</script>

6、修改状态数据 

1、直接修改和批量修改

<template>
  <div class="home">
    <p>{{ counterStore.count }}</p>
 
    <p @click="test">直接修改</p>
 
  </div>
</template>
 
<script setup lang="ts">
import { useCounterStore } from "@/store/counter";
 
const counterStore = useCounterStore();
 
const test = () => {
  counterStore.count++; // 直接修改
};
 
</script>

2、批量修改  $patch

<template>
  <div class="home">
    <p>{{ counterStore.msg }}</p>
    <p>{{ counterStore.count }}</p>
    <p>{{ counterStore.doubleCount }}</p>
 
    <p @click="test2">批量修改</p>
 
  </div>
</template>
 
<script setup lang="ts">
import { useCounterStore } from "@/store/counter";
 
const counterStore = useCounterStore();
 
const test2 = () => {
  // 批量修改
  counterStore.$patch((state) => {
    state.count = 10000,
    state.msg = '你好',
    state.todoList.push('看看')
  })
};
 
</script>

3、重置 $reset ，可把参数重置回原始参数

counterStore.$reset()

4、替换 $state ,也只能换原有的参数，和批量修改差不多

counterStore.$state = { counter: 666, msg: "Paimon", todoList: [] };

5、监听 state 数据变化 

counterStore.$subscribe((mutation: any, state: any) => {
  // 订阅 state 值的变化
  console.log("cart:" + JSON.stringify(state));
});