Sendgrid Node.js Error: Converting circular structure to JSON

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: "[email protected]",
  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: '[email protected]',
  from: '[email protected]',
  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' });