详解Vue3如何优雅的监听localStorage变化

// mediator.ts
export interface MediatorProps {
  uuid?: number;
  publish?: (topic: string, ...args: unknown[]) => void;
  subscribe?: (topic: string, callback: (...args: unknown[]) => void) => void;
}
const mediator = (function () {
  let topics = [],
    uuid = 0;
  function subscribe(topic: string, callback: (...args: unknown[]) => void) {
    uuid++;
    topics[topic] = topics[topic]
      ? [...topics[topic], { callback, uuid }]
      : [{ callback, uuid }];
  }
  function publish(topic: string, ...args: unknown[]) {
    if (topics[topic]) {
      topics[topic].map((item) => item.callback(...args));
    }
  }
  return {
    install: function (obj: MediatorProps) {
      obj.uuid = uuid;
      obj.publish = publish;
      obj.subscribe = subscribe;
      return obj;
    },
  };
})();
export default mediator;

// localStorage.ts
import mediator from "./mediator";
const keys: string[] = [];
const createMediator = () => mediator.install({});
const sub = createMediator();
export const $localStorage = {
  getItem: (key: string) => {
    return window.localStorage.getItem(key);
  },
  setItem: (key: string, value: any) => {
    // 防止重复发布
    if (!keys.includes(key)) keys.push(key);
    // 被修改就发布事件
    sub.publish(key, value);    
    window.localStorage.setItem(key, value);
  },
  clear: () => {
    // 被删除就每个key发布事件
    keys.map((key) => sub.publish(key, undefined));
    // 发布后清空记录key的数组
    keys.length = 0;
    window.localStorage.clear();
  },
  removeItem: (key: string) => {
    keys.splice(keys.indexOf(key), 1);
    // 被移除就发布 undefined
    sub.publish(key, undefined);
    window.localStorage.removeItem(key);
  },
  key: window.localStorage.key,
  length: window.localStorage.length,
};

// useStorage.ts
import { ref } from "vue";
import mediator from "./mediator";
const createMediator = () => mediator.install({});
 export const useStorage = (key: string) => {
  const string = ref(null);
  const sub = createMediator();
  sub.subscribe(key, (value) => string.value = value);
  return string;
};

// One.vue
// 使用localStorage
import { watch } from "vue";
import { useStorage } from "./hook";
const key = useStorage("yourKey");
watch([key], (a) => console.log(a));

// Two.vue
// 监听localStorage
<script setup lang="ts">
import { ref } from "vue";
import { localStorage } from "./hook";
const count = ref(0);
</script>
<template>
  <div>
      <button
        type="button"
        @click="$localStorage.setItem('a', count++);"
      >
        count is {{ count }}
      </button>
    </div>
</template>