beefree | An Implementation to the BeeFree.io email editor | Email library

The code underneath your call to fs.readFile is not provided as part of the callback to that function. Basically, the file read is being kicked off and the rest of the code begins execution, resulting in a race to create html_template before the email is sent.

Two solutions:

1. Extend the callback to include the rest of the code. This would be the preferred method, as it is non-blocking and thus allows your application to continue serving other requests.
2. Use fs.readFileSync, the synchronous equivalent.

Also, since you are using async/await, you could also just let data = await fs.readFile("path/to/file");