[No QA][TS migration] Migrate 'Visibility' lib to TypeScript

src/libs/Visibility/index.desktop.js → src/libs/Visibility/index.desktop.ts

@@ -4,28 +4,20 @@ import ELECTRON_EVENTS from '../../../desktop/ELECTRON_EVENTS';
  * Detects whether the app is visible or not. Electron supports document.visibilityState,
  * but switching to another app while Electron is partially occluded will not trigger a state of hidden
  * so we ask the main process synchronously whether the BrowserWindow.isFocused()
- *
- * @returns {Boolean}
  */
 function isVisible() {
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-return
     return window.electron.sendSync(ELECTRON_EVENTS.REQUEST_VISIBILITY);
 }
 
-/**
- * @returns {Boolean}
- */
 function hasFocus() {
     return true;
 }
 
 /**
  * Adds event listener for changes in visibility state
- *
- * @param {Function} callback
- *
- * @return {Function} removes the listener
  */
-function onVisibilityChange(callback) {
+function onVisibilityChange(callback: () => void) {
     // Deliberately strip callback argument to be consistent across implementations
     window.electron.on(ELECTRON_EVENTS.FOCUS, () => callback());
     window.electron.on(ELECTRON_EVENTS.BLUR, () => callback());

src/libs/Visibility/index.native.js → src/libs/Visibility/index.native.ts

@@ -3,26 +3,18 @@
 
 import {AppState} from 'react-native';
 
-/**
- * @return {Boolean}
- */
-const isVisible = () => AppState.currentState === 'active';
+function isVisible() {
+    return AppState.currentState === 'active';
+}
 
-/**
- * @returns {Boolean}
- */
 function hasFocus() {
     return true;
 }
 
 /**
  * Adds event listener for changes in visibility state
- *
- * @param {Function} callback
- *
- * @return {Function} removes the listener
  */
-function onVisibilityChange(callback) {
+function onVisibilityChange(callback: () => void) {
     // Deliberately strip callback argument to be consistent across implementations
     const subscription = AppState.addEventListener('change', () => callback());
 

src/libs/Visibility/index.js → src/libs/Visibility/index.ts

@@ -2,30 +2,22 @@ import {AppState} from 'react-native';
 
 /**
  * Detects whether the app is visible or not.
- *
- * @returns {Boolean}
  */
 function isVisible() {
     return document.visibilityState === 'visible';
 }
 
 /**
  * Whether the app is focused.
- *
- * @returns {Boolean}
  */
 function hasFocus() {
     return document.hasFocus();
 }
 
 /**
  * Adds event listener for changes in visibility state
- *
- * @param {Function} callback
- *
- * @return {Function} removes the listener
  */
-function onVisibilityChange(callback) {
+function onVisibilityChange(callback: () => void) {
     // Deliberately strip callback argument to be consistent across implementations
     const subscription = AppState.addEventListener('change', () => callback());
 

src/types/modules/electron.d.ts

@@ -0,0 +1,9 @@
+declare global {
+    // eslint-disable-next-line @typescript-eslint/consistent-type-definitions
+    interface Window {
+        electron: Electron;
+    }
+}
+
+// We used the export {} line to mark this file as an external module
+export {};