title: How to launch an external process synchronously in Electron
body: <p>In Electron, </p>
  
  <p>I need to call an external program to do some work, wait for it to finish and terminate, and then move on to my next line of code.</p>
  
  <p>I've tried <code>shell.openItem("/applications/apptocall.app")</code></p>
  
  <p>This works to launch the app, but it runs the next line of code in my electron app immediately instead of waiting for the externally launched app to finish.</p>
  
  <p>What is the easiest way to do this?</p>