blob: d9d62346518897e21264394ca445ef0a527fe33d [file] [log] [blame]
// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:async';
import 'dart:convert' show json;
import 'dart:html' as html;
import 'package:flutter_web_plugins/flutter_web_plugins.dart';
import 'package:shared_preferences_platform_interface/shared_preferences_platform_interface.dart';
/// The web implementation of [SharedPreferencesStorePlatform].
///
/// This class implements the `package:shared_preferences` functionality for the web.
class SharedPreferencesPlugin extends SharedPreferencesStorePlatform {
/// Registers this class as the default instance of [SharedPreferencesStorePlatform].
static void registerWith(Registrar? registrar) {
SharedPreferencesStorePlatform.instance = SharedPreferencesPlugin();
}
@override
Future<bool> clear() async {
// IMPORTANT: Do not use html.window.localStorage.clear() as that will
// remove _all_ local data, not just the keys prefixed with
// "flutter."
_storedFlutterKeys.forEach(html.window.localStorage.remove);
return true;
}
@override
Future<Map<String, Object>> getAll() async {
final Map<String, Object> allData = <String, Object>{};
for (final String key in _storedFlutterKeys) {
allData[key] = _decodeValue(html.window.localStorage[key]!);
}
return allData;
}
@override
Future<bool> remove(String key) async {
_checkPrefix(key);
html.window.localStorage.remove(key);
return true;
}
@override
Future<bool> setValue(String valueType, String key, Object? value) async {
_checkPrefix(key);
html.window.localStorage[key] = _encodeValue(value);
return true;
}
void _checkPrefix(String key) {
if (!key.startsWith('flutter.')) {
throw FormatException(
'Shared preferences keys must start with prefix "flutter.".',
key,
0,
);
}
}
Iterable<String> get _storedFlutterKeys {
return html.window.localStorage.keys
.where((String key) => key.startsWith('flutter.'));
}
String _encodeValue(Object? value) {
return json.encode(value);
}
Object _decodeValue(String encodedValue) {
final Object? decodedValue = json.decode(encodedValue);
if (decodedValue is List) {
// JSON does not preserve generics. The encode/decode roundtrip is
// `List<String>` => JSON => `List<dynamic>`. We have to explicitly
// restore the RTTI.
return decodedValue.cast<String>();
}
return decodedValue!;
}
}