This program is a Node.js application that enables the user to send an email using their Gmail account. The program uses the nodemailer package to handle email sending.
To run the program, you need to have Node.js and nodemailer installed. You can install nodemailer by running the following command:
npm install nodemailer
To use the program, you can create a new instance of the `EmailSender` class and call the `start` method. The `start` method prompts the user to select an option: send an email or exit.
If the user selects the option to send an email, the `sendEmailPrompt` method is called. The `sendEmailPrompt` method prompts the user to enter the recipient's email address, subject, message body, and HTML body (optional). Once the user enters the required information, the `sendEmail` method is called to send the email.
If the user selects the option to exit, the `rl.close()` method is called to close the readline interface and terminate the program.