我用的是nextjs app Dir。我需要发送电子邮件，我用nodemailer发送，我需要使用服务器组件，因为你不能用客户端发送。
我在这个项目中使用typescript，我有一些问题，使用的功能是服务器端到客户端。
我所做的
1.我创建了一个发送电子邮件并接受类型参数的函数，其中重要的一个是toEmail，它应该是一个字符串。我使用'use server'，因为我有其他错误，解决方案是使其成为服务器组件。

'use server'
import nodemailer from 'nodemailer';

const transporter = nodemailer.createTransport({
//   host: 'smtp.ethereal.email',
//   port: 587,
    service: 'gmail',
    secure: false,
        auth: {
            user: process.env.EMAIL,
            pass: process.env.EMAIL_PASSWORD,
        },
});

export const sendEmail = async (toEmail: string, subject: string, html: string) => {
    await transporter.sendMail({
        from :      process.env.EMAIL_ADMIN_QUOTE_RECEIVER,
        to:         toEmail,
        subject:    subject,
        html:       html
    });
};
```;


2. Secondly, I created the client component that gets the state and finally the one that sends the email. However, Because I want to use env variables, the `toEmail` parameter cannot accept `string | undefined`, because it should be strictly a string. If i log the `process.env.EMAIL_ADMIN_QUOTE_RECEIVER` in the console, I get the result in the server console, but in the browser is undefined.... 
This component is a 'use client' component

Here is the function:

const handleSendQuote = async（event：System. out. println（）;

const emailHTML = render(<NewQuoteReceived 
    name={fullName}                         dateRequired={dateRequired}
    vechNeeded={vechiclesRequired}          serviceReq={service}
    phone={phoneNumber}                     email={email} 
    details={details} />)
  
  
await sendEmail(process.env.EMAIL_ADMIN_QUOTE_RECEIVER, 'New quote received', emailHTML);
alert('Sent');
 
clearState();

}