@capacitor/preferences

Preferences APIは、軽量なデータのためのシンプルなキー/バリューの永続ストアを提供します。

モバイル OS は定期的に window.localStorage に保存されたデータを消去することがあるので、 代わりにこの API を使用する必要があります。 この API は Progressive Web App として動作している場合、localStorage を使用するようにフォールバックします。

このプラグインは、iOS では UserDefaults を、 Windows では SharedPreferences を使用します。 Android では SharedPreferences を 使用します。 保存されたデータは、アプリがアンインストールされると消去されます。

注意: このAPIは、ローカルデータベースとして使用することは想定していません。アプリが多くのデータを アプリが大量のデータを保存する場合、読み取り/書き込みの負荷が高い場合、または複雑なクエリを必要とする場合。 SQLiteベースのソリューションを検討することをお勧めします。そのようなソリューションの1つが、完全な暗号化をサポートするSQLiteベースのエンジンであるIonic Secure Storageです。Capacitor Community](https://github.com/capacitor-community/) は、他にも多くのストレージエンジンを構築しています。

Install

npm install @capacitor/preferences
npx cap sync

Apple Privacy Manifest Requirements

Apple mandates that app developers now specify approved reasons for API usage to enhance user privacy. By May 1st, 2024, it's required to include these reasons when submitting apps to the App Store Connect.

When using this specific plugin in your app, you must create a PrivacyInfo.xcprivacy file in /ios/App or use the VS Code Extension to generate it, specifying the usage reasons.

For detailed steps on how to do this, please see the Capacitor Docs.

For this plugin, the required dictionary key is NSPrivacyAccessedAPICategoryUserDefaults and the recommended reason is CA92.1.

Example PrivacyInfo.xcprivacy

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>NSPrivacyAccessedAPITypes</key>
    <array>
      <!-- Add this dict entry to the array if the PrivacyInfo file already exists -->
      <dict>
        <key>NSPrivacyAccessedAPIType</key>
        <string>NSPrivacyAccessedAPICategoryUserDefaults</string>
        <key>NSPrivacyAccessedAPITypeReasons</key>
        <array>
          <string>CA92.1</string>
        </array>
      </dict>
    </array>
  </dict>
</plist>

Example Plugin Usage

import { Preferences } from '@capacitor/preferences';

const setName = async () => {
  await Preferences.set({
    key: 'name',
    value: 'Max',
  });
};

const checkName = async () => {
  const { value } = await Preferences.get({ key: 'name' });

  console.log(`Hello ${value}!`);
};

const removeName = async () => {
  await Preferences.remove({ key: 'name' });
};

Working with JSON

The Preferences API only supports string values. You can, however, use JSON if you JSON.stringify the object before calling set(), then JSON.parse the value returned from get().

This method can also be used to store non-string values, such as numbers and booleans.

API

• configure(...)
• get(...)
• set(...)
• remove(...)
• clear()
• keys()
• migrate()
• removeOld()
• Interfaces

configure(...)

configure(options: ConfigureOptions) => Promise<void>

Configure the preferences plugin at runtime.

Options that are undefined will not be used.

Param	Type
options	ConfigureOptions

Since: 1.0.0

---

get(...)

get(options: GetOptions) => Promise<GetResult>

Get the value from preferences of a given key.

Param	Type
options	GetOptions

Returns:

Promise<GetResult>

Since: 1.0.0

---

set(...)

set(options: SetOptions) => Promise<void>

Set the value in preferences for a given key.

Param	Type
options	SetOptions

Since: 1.0.0

---

remove(...)

remove(options: RemoveOptions) => Promise<void>

Remove the value from preferences for a given key, if any.

Param	Type
options	RemoveOptions

Since: 1.0.0

---

clear()

clear() => Promise<void>

Clear keys and values from preferences.

Since: 1.0.0

---

keys()

keys() => Promise<KeysResult>

Return the list of known keys in preferences.

Returns:

Promise<KeysResult>

Since: 1.0.0

---

migrate()

migrate() => Promise<MigrateResult>

Migrate data from the Capacitor 2 Storage plugin.

This action is non-destructive. It will not remove old data and will only write new data if they key was not already set. To remove the old data after being migrated, call removeOld().

Returns:

Promise<MigrateResult>

Since: 1.0.0

---

removeOld()

removeOld() => Promise<void>

Removes old data with _cap_ prefix from the Capacitor 2 Storage plugin.

Since: 1.1.0

---

Interfaces

ConfigureOptions

Prop	Type	Description	Default	Since
group	string	Set the preferences group. Preferences groups are used to organize key/value pairs. Using the value 'NativeStorage' provides backwards-compatibility with cordova-plugin-nativestorage. WARNING: The clear() method can delete unintended values when using the 'NativeStorage' group.	CapacitorStorage	1.0.0

GetResult

Prop	Type	Description	Since
value	string | null	The value from preferences associated with the given key. If a value was not previously set or was removed, value will be null.	1.0.0

GetOptions

Prop	Type	Description	Since
key	string	The key whose value to retrieve from preferences.	1.0.0

SetOptions

Prop	Type	Description	Since
key	string	The key to associate with the value being set in preferences.	1.0.0
value	string	The value to set in preferences with the associated key.	1.0.0

RemoveOptions

Prop	Type	Description	Since
key	string	The key whose value to remove from preferences.	1.0.0

KeysResult

Prop	Type	Description	Since
keys	string[]	The known keys in preferences.	1.0.0

MigrateResult

Prop	Type	Description	Since
migrated	string[]	An array of keys that were migrated.	1.0.0
existing	string[]	An array of keys that were already migrated or otherwise exist in preferences that had a value in the Capacitor 2 Preferences plugin.	1.0.0