SCRIPT SAMPLE TO REPLACE THE VALUES OF EMAIL TEMPLATE

this code sample is used to update the content of the email template and use the html code to include the link to a suitelet that needs the customer id as parameter.

     const unsubscribeLink = `${SUITELET_URL}&customerId=${customer.id}`; //here the suilet_url is define globally 
                const linkHtml = `
                    <p style="margin-top: 20px; font-size: 12px; font-family: Arial, sans-serif; text-align: center; color: #666;">
                        <a href="${unsubscribeLink}" style="color: #007bff; text-decoration: none;">
                            Click here to unsubscribe.
                        </a>
                    </p>`;
                // Merge the email template
                const mergeResult = render.mergeEmail({
                    templateId: EMAIL_TEMPLATE_ID,
                    entity: { type: 'customer', id: parseInt(customer.id) },
                });
        
                // Replace placeholders in the email body
                let emailBody = mergeResult.body;
                emailBody = emailBody.replace('#link#', linkHtml);

the emailBody is the template and inside the template we have defined #link that is where we need the link to be displayed and this is replaced with the linkHtml.

here this link in the email template is replaced in the email content.