import Stigg from '@stigg/typescript';

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

const response = await client.v1.subscriptions.preview({
  customerId: 'customerId',
  planId: 'planId',
});

console.log(response.data);

{
  "data": {
    "immediateInvoice": {
      "total": 123,
      "subTotal": 123,
      "discount": 123,
      "tax": 123,
      "currency": "<string>",
      "lines": [
        {
          "description": "<string>",
          "unitPrice": 123,
          "subTotal": 123,
          "currency": "<string>",
          "quantity": 123
        }
      ],
      "discounts": [
        {
          "description": "<string>",
          "amount": 123,
          "currency": "<string>"
        }
      ],
      "discountDetails": {
        "code": "<string>",
        "percentage": 123,
        "fixedAmount": 123
      }
    },
    "billingPeriodRange": {
      "start": "2023-11-07T05:31:56Z",
      "end": "2023-11-07T05:31:56Z"
    },
    "isPlanDowngrade": true,
    "hasScheduledUpdates": true,
    "freeItems": [
      {
        "id": "<string>",
        "quantity": 1
      }
    ]
  }
}