The `LocalStorage` API is a plain text key/value holding persistent storage for spotube plugins. It's similar to the `localStorage` API in web browsers.
The API is a 1:1 port of [shared_preferences][shared_preferences] package from [pub.dev](https://pub.dev) (Flutter package registry)

The only difference is that the `LocalStorage` API is 100% asynchronous. So every method returns a `Future`

## Usage

#### Get values

Retrieve stored information by key:

```javascript
import "module:spotube_plugin" as spotube

var LocalStorage = spotube.LocalStorage

// Get a string value by key
LocalStorage.getString("key").then((value) {
    print("Value for 'key': $value")
})

// Get an integer value by key
LocalStorage.getInt("key").then((value) {
    print("Value for 'key': $value")
})

// Get a double value by key
LocalStorage.getDouble("key").then((value) {
    print("Value for 'key': $value")
})

// Get a boolean value by key
LocalStorage.getBool("key").then((value) {
    print("Value for 'key': $value")
})

// Get a list of strings by key
LocalStorage.getStringList("key").then((value) {
    for (var item in value) {
        print("Item in list: $item")
    }
})
```

#### Set values

To set or store data in the local storage, you can use the following methods:

```javascript
// Set a string value by key
LocalStorage.setString("key", "value")

// Set an integer value by key
LocalStorage.setInt("key", 42)

// Set a double value by key
LocalStorage.setDouble("key", 3.14)

// Set a boolean value by key
LocalStorage.setBool("key", true)

// Set a list of strings by key
LocalStorage.setStringList("key", ["item1", "item2", "item3"])
```

#### Key operations

To remove a value from the local storage, you can use the `remove` method:

```javascript
// Remove a value by key
LocalStorage.remove("key")
```

To clear all values from the local storage, you can use the `clear` method:

```javascript
// Clear all values from local storage
LocalStorage.clear()
```

To check if a key exists in the local storage, you can use the `containsKey` method:

```javascript
// Check if a key exists
LocalStorage.containsKey("key").then((exists) {
    if (exists) {
        print("Key 'key' exists in local storage")
    } else {
        print("Key 'key' does not exist in local storage")
    }
})
```

[shared_preferences]: https://pub.dev/packages/shared_preferences