fix: simplify window / app close behavior

Closes #142

js/src/main.ts

@@ -51,6 +51,7 @@ const createWindow = () => {
 
   mainWindow.on('closed', () => {
     mainWindow = null;
+    app.quit();
   });
 };
 
@@ -419,20 +420,16 @@ app.on('ready', () => {
   createAutoplayWindow();
 });
 
-// Quit when all windows are closed, except on macOS. There, it's common
-// for applications and their menu bar to stay active until the user quits
-// explicitly with Cmd + Q.
 app.on('window-all-closed', () => {
-  if (process.platform !== 'darwin') {
+  app.quit();
-    app.quit();
-  }
 });
 
 app.on('activate', () => {
-  // On OS X it's common to re-create a window in the app when the
+  if (!mainWindow) {
-  // dock icon is clicked and there are no other windows open.
-  if (BrowserWindow.getAllWindows().length === 0) {
     createWindow();
+  } else {
+    mainWindow.show();
+    mainWindow.focus();
   }
 });