const inputBody = '{
  "type": "object",
  "properties": {
    "customerItems": {
      "type": "array",
      "description": "List of customer item MongoDB ObjectIds to export or exclude",
      "items": {
        "type": "string",
        "format": "mongoId"
      }
    },
    "selectAll": {
      "type": "boolean",
      "description": "If true, export all customer items except those listed in `customerItems`"
    }
  },
  "required": [
    "selectAll"
  ]
}';
const headers = {
  'Content-Type':'application/json',
  'Accept':'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
};

fetch('https://goldleaf.app/api/v1/customer/{customerId}/items/export',
{
  method: 'POST',
  body: inputBody,
  headers: headers
})
.then(function(res) {
    return res.json();
}).then(function(body) {
    console.log(body);
});