import Courier from '@trycourier/courier';

const client = new Courier({
  apiKey: process.env['COURIER_API_KEY'], // This is the default and can be omitted
});

const preference = await client.users.preferences.retrieve('user_id');

console.log(preference.items);

{
  "paging": {
    "more": true,
    "cursor": "<string>"
  },
  "items": [
    {
      "topic_id": "<string>",
      "topic_name": "<string>",
      "custom_routing": [],
      "has_custom_routing": true
    }
  ]
}