getJson static method
Retrieves cached JSON data if it's not expired.
Implementation
static Future<dynamic> getJson(String key) async {
await _init();
final String? cachedData = _prefs?.getString('cache_$key');
if (cachedData == null) return null;
final Map<String, dynamic> data = json.decode(cachedData);
final int expiry = data['expiry'] ?? 0;
if (DateTime.now().millisecondsSinceEpoch > expiry) {
await _prefs?.remove('cache_$key');
return null;
}
return data['content'];
}