feat: new KeyboardController.isVisible() method (#694)

## 📜 Description

Added `KeyboardController.isVisible()` method.

## 💡 Motivation and Context

I decided to match `Keyboard` API from `react-native` more closely, and
I thought that `isVisible()` method can be useful in many places.

So in this PR I'm adding `isVisible` method.

## 📢 Changelog

<!-- High level overview of important changes -->
<!-- For example: fixed status bar manipulation; added new types
declarations; -->
<!-- If your changes don't affect one of platform/language below - then
remove this platform/language -->

### Docs

- added API spec for new method.

### JS

- added `isVisible` method to `KeyboardController` API.

## 🤔 How Has This Been Tested?

Tested manually.

## 📝 Checklist

- [x] CI successfully passed
- [x] I added new mocks and corresponding unit-tests if library API was
changed

docs/docs/api/keyboard-controller.md

@@ -70,6 +70,20 @@ The equivalent method from `react-native` relies on specific internal components
 In contrast, the described method enables keyboard dismissal for any focused input, extending functionality beyond the limitations of the default implementation.
 :::
 
+### `isVisible`
+
+```ts
+static isVisible(): boolean;
+```
+
+This method returns `true` if keyboard is currently visible and `false` otherwise.
+
+```ts
+if (KeyboardController.isVisible()) {
+  // do something
+}
+```
+
 ### `setFocusTo`
 
 ```ts

jest/index.js

@@ -51,6 +51,7 @@ const mock = {
     setDefaultMode: jest.fn(),
     dismiss: jest.fn().mockReturnValue(Promise.resolve()),
     setFocusTo: jest.fn(),
+    isVisible: jest.fn().mockReturnValue(false),
   },
   AndroidSoftInputModes: {
     SOFT_INPUT_ADJUST_NOTHING: 48,

src/module.ts

@@ -2,19 +2,19 @@ import { KeyboardControllerNative, KeyboardEvents } from "./bindings";
 
 import type { KeyboardControllerModule } from "./types";
 
-let isVisible = false;
+let isClosed = false;
 
 KeyboardEvents.addListener("keyboardDidHide", () => {
-  isVisible = false;
+  isClosed = true;
 });
 
 KeyboardEvents.addListener("keyboardDidShow", () => {
-  isVisible = true;
+  isClosed = false;
 });
 
 const dismiss = async (): Promise<void> => {
   return new Promise((resolve) => {
-    if (!isVisible) {
+    if (isClosed) {
       resolve();
 
       return;
@@ -28,10 +28,12 @@ const dismiss = async (): Promise<void> => {
     KeyboardControllerNative.dismiss();
   });
 };
+const isVisible = () => !isClosed;
 
 export const KeyboardController: KeyboardControllerModule = {
   setDefaultMode: KeyboardControllerNative.setDefaultMode,
   setInputMode: KeyboardControllerNative.setInputMode,
   setFocusTo: KeyboardControllerNative.setFocusTo,
   dismiss: dismiss,
+  isVisible,
 };

src/types.ts

@@ -121,6 +121,7 @@ export type KeyboardControllerModule = {
   // all platforms
   dismiss: () => Promise<void>;
   setFocusTo: (direction: Direction) => void;
+  isVisible: () => boolean;
 };
 export type KeyboardControllerNativeModule = {
   // android only