> For the complete documentation index, see [llms.txt](https://thisistails.gitbook.io/tailslib/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://thisistails.gitbook.io/tailslib/tailslib-rus/custom-items/nbt-state.md).

# NBT State

In this page we gonna learn how to use `NBTState` in TailsLib.

## What is NBTState?

`NBTState` is basicly wrapper for `PersistentDataContainer` (PDC) inspired by React.js `useState` .

Nothing fancy really.

## Usage

To use `NBTState` we need a type that `NBTState` gonna use for access `PDC` and that means we need `PersistentDataType`. You could create your own `PersistentDataType` to automaticly convert data from `PDC` to your object.

So basicly we have 2 constructors.

```java
public NBTState(String key, PersistentDataType<?, T> type)
public NBTState(String key, PersistentDataType<?, T> type, T defaultValue)
```

Just create a field with one of constructors.

```java
public final NBTState<Integer> clicksState = new NBTState<>(
    "clicks", // Key of NBT
    PersistentDataType.INTEGER, // Type 
    0 // Default value to be set
);
```

To access and write data to `PDC` with this state we use

```java
ItemStack item = new ItemStack(Material.DIAMOND);

// Will return 0 since item does not have any NBT
// This operation also will automaticly write 0 to NBT of this item
int clicks = clicksState.get(item);

clicksState.set(item, 10); // Set clicks to 10 for this item.
clicks = clicksState.get(item); // Now will return 10.
```

There's example if without default value

```java
NBTState<String> someState = new NBTState<>(
    "something", // Key of NBT
    PersistentDataType.STRING // Type 
);

ItemStack item = new ItemStack(Material.DIAMOND);
String something = someState.get(item); // Will return null
```


---

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