[1908] layout not exec when refresh current page

I want dynamic change my theme when user select theme, i put theme value to localStorage,this is my code,

  layout (context) {
    if (context.isClient) {
      // return context.app.store.state.theme.theme.current === '0' ? '' : 'dark'
      return localStorage.getItem('theme')
    }
  }

but, when i refresh current page, the layout method not run