更良好的读取持久化数据

全局变量代理

做一个全局变量代理 放在运存中

这里全局变量举例 window._theme

• 读

  const getTheme = () => {
    return window._theme || window.localStorage.getItem('theme') || 'default'
  }
  

• 写

  const setTheme = (value) => {
    window.localStorage.setItem('theme': value)
    return window._theme = value
  }
  

监听localStorage变化

重写localStorage

var orignalSetItem = localStorage.setItem;
localStorage.setItem = function(key,newValue){
      var setItemEvent = new Event("setItemEvent");
      setItemEvent.newValue = newValue;
      window.dispatchEvent(setItemEvent);
      orignalSetItem.apply(this,arguments);
}
window.addEventListener("setItemEvent", function (e) {
    alert(e.newValue);
});
localStorage.setItem("name","wang");