Sendgrid Node.js Error: Converting circular structure to JSON - node.js

Question

I'm using Sendgrid to send a transactional Email with Firebase Cloud Functions using Nodejs.
const attachment = file.createReadStream();
const msg = {
to: email,
from: "test#test.com",
subject: "print order",
templateId: "templateid",
dynamic_template_data: {
dashboardurl: `/order#${orderId}`,
downloadurl: orderData.downloadurl
},
attachments: [{
content: attachment,
filename: "order.pdf",
type: "application/pdf",
disposition: "attachment"
}]
};
await sgMail.send(msg);
The Email won't send, because of the following bug:
TypeError: Converting circular structure to JSON
Solution for Firebase Storage
const tempFilePath = path.join(os.tmpdir(), "tmp.pdf");
await file.download({ destination: tempFilePath });
const attachment = fs.readFileSync(tempFilePath, { encoding: "base64" });

Answer 1

According to doc:
For content you send base64 encoded version of the file.
const sgMail = require('#sendgrid/mail');
sgMail.setApiKey(process.env.SENDGRID_API_KEY);
const msg = {
to: 'recipient#example.org',
from: 'sender#example.org',
subject: 'Hello attachment',
html: '<p>Here’s an attachment for you!</p>',
attachments: [
{
content: 'Some base 64 encoded attachment content',
filename: 'some-attachment.txt',
type: 'plain/text',
disposition: 'attachment',
contentId: 'mytext'
},
],
};
So in your case below conversion would suffice:
const attachment = fs.readFileSync('filepath', { encoding: 'base64' });