Elasticsearch scrolling data extraction

dumper.js

const ElasticSearch = require('elasticsearch')

function scrollingSearch (es, index, type, size, scroll, body, stagger = 0) {
  return {
    [Symbol.asyncIterator]: async function* next () {
      let count = 0
      let r = await es.search({ index, type, size, scroll, body })
      while (count < r.hits.total) {
        for (let hit of r.hits.hits) {
          await new Promise((resolve, reject) => setTimeout(resolve, stagger))
          yield hit._source
          count++
        }
        r = await es.scroll({ scrollId: r._scroll_id, scroll })
      }
    }
  }
}

(async function () {
  let es = new ElasticSearch.Client({
    host: 'http://mes01.a.tt.se:9200'
  })

  for await (let hit of scrollingSearch(es, 'dist-text', 'ttninjs', 500, '5m', {
    query: {
      range: {
        versioncreated: {
          gte: '2018-01-30',
          lte: '2019-12-16'
        }
      }
    }
  })) {
    console.log(hit.versioncreated)
  }
})()