const { result, error } = await unprice.customers.getActivePhase("cus_1234567890");

if (error) {
  // handle potential network or bad request error
  // a link to our docs will be in the `error.docs` field
  console.error(error.message);
  return;
}

console.log(result);

{
  "phase": {
    "id": "phase_1234567890",
    "startDate": 1678900000,
    "endDate": 1681492000,
    "planVersionId": "pv_1234567890",
    "status": "active"
  }
}