const havePrefs = typeof window.localStorage !== 'undefined'; export default class Prefs { havePrefs() { return havePrefs; } readPref(name: string): string | null readPref(name: string, defaultValue: string): string readPref(name: string, defaultValue: string | null = null) { if (havePrefs) { return window.localStorage.getItem(name) ?? defaultValue; } return defaultValue; } writePref(name: string, value: string) { if (havePrefs) { window.localStorage.setItem(name, value); } } }