Behave like a single-window Mac app on Mac

electron/src/electron-main.js

@@ -2,6 +2,7 @@
 const {app, BrowserWindow} = require('electron');
 
 let mainWindow = null;
+let appQuitting = false;
 
 app.on('ready', () => {
     mainWindow = new BrowserWindow({
@@ -12,8 +13,26 @@ app.on('ready', () => {
     mainWindow.on('closed', () => {
         mainWindow = null;
     });
+    mainWindow.on('close', (e) => {
+        if (process.platform == 'darwin' && !appQuitting) {
+            // On Mac, closing the window just hides it
+            // (this is generally how single-window Mac apps
+            // behave, eg. Mail.app)
+            e.preventDefault();
+            mainWindow.hide();
+            return false;
+        }
+    });
 });
 
 app.on('window-all-closed', () => {
     app.quit();
 });
+
+app.on('activate', () => {
+    mainWindow.show();
+});
+
+app.on('before-quit', () => {
+    appQuitting = true;
+});