const options = {
  method: 'PATCH',
  headers: {'x-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    values: [
      {
        kpi_id: '3c90c3cc-0d44-4b50-8888-8dd25736052a',
        value_numeric: 123,
        value_text: '<string>',
        value_date: '2023-12-25'
      }
    ],
    attachment_file_ids: ['3c90c3cc-0d44-4b50-8888-8dd25736052a']
  })
};

fetch('https://api.dcycle.io/v1/custom-kpi-datasets/{dataset_id}/campaigns/{campaign_id}/assignments/{campaign_assignment_id}/values', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

[
  {
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "assignment_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "kpi_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "submitted_at": "2023-11-07T05:31:56Z",
    "created_at": "2023-11-07T05:31:56Z",
    "value_numeric": 123,
    "value_text": "<string>",
    "value_date": "2023-12-25",
    "submitter_email": "<string>",
    "submitter_user_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
  }
]