Make sure tsconfig be used.

main.ts

@@ -2,6 +2,8 @@ import { app, BrowserWindow, screen } from 'electron';
 import * as path from 'path';
 import * as url from 'url';
 
+import {interval} from 'rxjs';
+
 let win, serve;
 const args = process.argv.slice(1);
 serve = args.some(val => val === '--serve');
@@ -40,6 +42,8 @@ function createWindow() {
     // when you should delete the corresponding element.
     win = null;
   });
+
+  interval(1000).subscribe(val => console.log(`ES5 works fine : @${val}s`));
 }
 
 try {