Disclaimer:
These pages about different languages / apis / best practices were mostly jotted down quckily and rarely corrected afterwards.
The languages / apis / best practices may have changed over time (e.g. the facebook api being a prime example), so what was documented as a good way to do something at the time might be outdated when you read it (some pages here are over 15 years old).
Just as a reminder.

var options = {
  key: fs.readFileSync('/tmp/your_own.pem'),
  cert: fs.readFileSync('/tmp/your_own.pem')
};