npm install pinia

import { createApp } from 'vue';
import { createPinia } from 'pinia';
import App from './App.vue';

const pinia = createPinia();
const app = createApp(App);
app.use(pinia);
app.mount('#app');

import { defineStore } from 'pinia';

// 第一個參數(shù)是store的唯一ID，第二個參數(shù)是一個函數(shù)，返回store的配置對象
export const useCounterStore = defineStore('counter', {
  // 類似于Vuex中的state，存儲數(shù)據(jù)
  state: () => {
    return {
      count: 0
    };
  },
  // 類似于Vuex中的getters，用于派生數(shù)據(jù)
  getters: {
    doubleCount: (state) => {
      return state.count * 2;
    }
  },
  // 類似于Vuex中的actions和mutations的組合，用于修改state
  actions: {
    increment() {
      this.count++;
    },
    decrement() {
      this.count--;
    }
  }
});

<template>
  <div>
    <p>當(dāng)前計數(shù): {{ counter.count }}</p>
    <p>雙倍計數(shù): {{ counter.doubleCount }}</p>
    <button @click="counter.increment()">增加計數(shù)</button>
    <button @click="counter.decrement()">減少計數(shù)</button>
  </div>
</template>
<script>
import { useCounterStore } from './store.js';

export default {
  setup() {
    const counter = useCounterStore();
    return { counter };
  }
};
</script>

import { useCounterStore } from './store.js';

const counterStore = useCounterStore();
console.log(counterStore.count);
counterStore.increment();