Accessing 'getWeekOfWeekyear()' when aggregating

Elastic Stack Elasticsearch
2

I guess that was a tough one... This is the working script I've came up with:

GET /unittesttg1_tg1_fq1/_search
{
  "size": 0,
  "aggs": {
    "groupby": {
      "terms": {
        "script": {
          "inline": "ZonedDateTime ztz = ZonedDateTime.ofInstant(Instant.ofEpochMilli(doc['LAST_MODIFIED_DATE'].value), ZoneId.of('UTC')); ztz.get(IsoFields.WEEK_OF_WEEK_BASED_YEAR);"
        },
        "size": 60
      }
    }
  }
}