# Paging

## Commands

### `goToPage`

Navigates to the specified page in the flipbook.

```javascript
instance.paging.goToPage(4);
```

### `goToNextPage`

Navigates to the next page in the flipbook. If the flipbook has a spread-based layout, it will navigate to the next spread.

```javascript
instance.paging.goToNextPage();
```

### `goToPrevPage`

Navigates to the previous page in the flipbook. If the flipbook has a spread-based layout, it will navigate to the previous spread.

```javascript
instance.paging.goToPrevPage();
```

### `getState`

Gets the current paging state.

```javascript
// You can either await the result of the command
const result = await instance.paging.getState();

// OR pass a callback
instance.paging.getState((result) => {
    // YOUR CODE HERE
});
```

The command will return an object with the following properties:

| Property        | Type                | Description                               |
| --------------- | ------------------- | ----------------------------------------- |
| `currentSpread` | `number[]`          | The current visible pages of the flipbook |
| `spreads`       | Array of `number[]` | All spreads of the flipbook               |
| `totalPages`    | `number`            | Total amount of pages in the flipbook     |

## Events

### `onChange`

This subscription will trigger when the spread of a flipbook changes.

```javascript
instance.paging.onChange((result) => {
    // YOUR CODE HERE
});
```

The callback contains a value/result with the following properties:

| Property        | Type                | Description                               |
| --------------- | ------------------- | ----------------------------------------- |
| `currentSpread` | `number[]`          | The current visible pages of the flipbook |
| `spreads`       | Array of `number[]` | All spreads of the flipbook               |
| `totalPages`    | `number`            | Total amount of pages in the flipbook     |