await sendEmail (req.body.email, this.verificationCode) throws an error:

this.verificationCode = undefined

How can I fix this?

class VerificationCodeController{

  constructor(){
    this.verificationCode = generateCode()
  }

  async sendCode(req, res){
    await sendEmail(req.body.email, this.verificationCode)
    return res.json(responseCreator.response(this.verificationCode));
  }

}