import Telnyx from 'telnyx';

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

const response = await client.list.retrieveByZone('channel_zone_id');

console.log(response.data);

{
  "data": [
    {
      "zone_name": "Euro channel zone",
      "zone_id": "1653e6a1-4bfd-4857-97c6-6a51e1c34477",
      "number_of_channels": 7,
      "numbers": [
        {
          "number": "+15554441234",
          "country": "FR"
        }
      ]
    }
  ],
  "meta": {
    "total_pages": 3,
    "page_number": 2,
    "total_results": 55,
    "page_size": 25
  }
}