import Telnyx from 'telnyx';

const client = new Telnyx({
  apiKey: 'My API Key',
});

const phoneNumberExtension = await client.portingOrders.phoneNumberExtensions.create(
  '182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e',
  {
    activation_ranges: [{ end_at: 10, start_at: 1 }],
    extension_range: { end_at: 10, start_at: 1 },
    porting_phone_number_id: 'f24151b6-3389-41d3-8747-7dd8c681e5e2',
  },
);

console.log(phoneNumberExtension.data);

{
  "data": {
    "id": "f24151b6-3389-41d3-8747-7dd8c681e5e2",
    "porting_phone_number_id": "f24151b6-3389-41d3-8747-7dd8c681e5e2",
    "extension_range": {
      "start_at": 1,
      "end_at": 10
    },
    "activation_ranges": [
      {
        "start_at": 1,
        "end_at": 10
      }
    ],
    "record_type": "porting_phone_number_extension",
    "created_at": "2021-03-19T10:07:15.527Z",
    "updated_at": "2021-03-19T10:07:15.527Z"
  }
}