Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

// Atlas Database Trigger — fires on every new order insert
// (Function code, written in the Atlas UI)

exports = async function(changeEvent) {
  // changeEvent.fullDocument is the inserted/updated document
  const order = changeEvent.fullDocument

// Access another collection via the context
  const db = context.services.get("mongodb-atlas").db("shop")
  const notifications = db.collection("notifications")

// Insert a notification document
  await notifications.insertOne({
    userId: order.userId,
    message: `Your order #${order._id} has been received.`,
    createdAt: new Date(),
    read: false
  })

// Call an external webhook (e.g. send email via SendGrid)
  const response = await context.http.post({
    url: "https://api.sendgrid.com/v3/mail/send",
    headers: {
      "Authorization": [`Bearer ${context.values.get("SENDGRID_KEY")}`],
      "Content-Type": ["application/json"]
    },
    body: JSON.stringify({
      to: [{ email: order.customerEmail }],
      from: { email: "noreply@myshop.com" },
      subject: "Order Confirmed",
      content: [{ type: "text/plain", value: `Order ${order._id} confirmed!` }]
    })
  })
  return response.status
}