SOLID - OCP - CORRECT EXAMPLE

solid-ocp-correct-two.ts

interface IEmailSend {
  send(): boolean;
}
class htmlEmail implements IEmailSend {
  
  public function send () {
    return util.sendEmail(this.email, this.user);
  }

}

class plainTextEmail implements IEmailSend {

  public function send () {
    return util.sendEmail(this.email, this.user);
  }

}

class numericEmail implements IEmailSend {

  public function send () {
    return util.sendEmail(this.email, this.user);
  }

}