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Co-authored-by: Josh Mock <josh@joshmock.com>

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Co-authored-by: Josh Mock <josh@joshmock.com>

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---------

Co-authored-by: Marci W <333176+marciw@users.noreply.github.com>
Co-authored-by: Josh Mock <josh@joshmock.com>

docs/reference/scroll_examples.md

@@ -0,0 +1,193 @@
+---
+mapped_pages:
+  - https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/scroll_examples.html
+---
+
+# Scroll [scroll_examples]
+
+While a search request returns a single “page” of results, the scroll API can be used to retrieve large numbers of results (or even all results) from a single search request, in much the same way as you would use a cursor on a traditional database.
+
+Scrolling is not intended for real time user requests, but rather for processing large amounts of data, for example in order to reindex the contents of one index into a new index with a different configuration.
+
+::::{note}
+The results that are returned from a scroll request reflect the state of the index at the time that the initial search request was made, like a snapshot in time. Subsequent changes to documents (index, update or delete) will only affect later search requests.
+::::
+
+
+In order to use scrolling, the initial search request should specify the scroll parameter in the query string, which tells {{es}} how long it should keep the “search context” alive.
+
+::::{note}
+Did you know that we provide an helper for sending scroll requests? You can find it [here](/reference/client-helpers.md#scroll-search-helper).
+::::
+
+
+```js
+'use strict'
+
+const { Client } = require('@elastic/elasticsearch')
+const client = new Client({
+  cloud: { id: '<cloud-id>' },
+  auth: { apiKey: 'base64EncodedKey' }
+})
+
+async function run () {
+  const allQuotes = []
+  const responseQueue = []
+
+  // Let's index some data!
+  const bulkResponse = await client.bulk({
+    // here we are forcing an index refresh,
+    // otherwise we will not get any result
+    // in the consequent search
+    refresh: true,
+    operations: [
+      // operation to perform
+      { index: { _index: 'game-of-thrones' } },
+      // the document to index
+      {
+        character: 'Ned Stark',
+        quote: 'Winter is coming.'
+      },
+
+      { index: { _index: 'game-of-thrones' } },
+      {
+        character: 'Daenerys Targaryen',
+        quote: 'I am the blood of the dragon.'
+      },
+
+      { index: { _index: 'game-of-thrones' } },
+      {
+        character: 'Tyrion Lannister',
+        quote: 'A mind needs books like a sword needs a whetstone.'
+      }
+    ]
+  })
+
+  if (bulkResponse.errors) {
+    console.log(bulkResponse)
+    process.exit(1)
+  }
+
+  // start things off by searching, setting a scroll timeout, and pushing
+  // our first response into the queue to be processed
+  const response = await client.search({
+    index: 'game-of-thrones',
+    // keep the search results "scrollable" for 30 seconds
+    scroll: '30s',
+    // for the sake of this example, we will get only one result per search
+    size: 1,
+    // filter the source to only include the quote field
+    _source: ['quote'],
+    query: {
+      match_all: {}
+    }
+  })
+
+  responseQueue.push(response)
+
+  while (responseQueue.length) {
+    const body = responseQueue.shift()
+
+    // collect the titles from this response
+    body.hits.hits.forEach(function (hit) {
+      allQuotes.push(hit._source.quote)
+    })
+
+    // check to see if we have collected all of the quotes
+    if (body.hits.total.value === allQuotes.length) {
+      console.log('Every quote', allQuotes)
+      break
+    }
+
+    // get the next response if there are more quotes to fetch
+    responseQueue.push(
+      await client.scroll({
+        scroll_id: body._scroll_id,
+        scroll: '30s'
+      })
+    )
+  }
+}
+
+run().catch(console.log)
+```
+
+Another cool usage of the `scroll` API can be done with Node.js ≥ 10, by using async iteration!
+
+```js
+'use strict'
+
+const { Client } = require('@elastic/elasticsearch')
+const client = new Client({
+  cloud: { id: '<cloud-id>' },
+  auth: { apiKey: 'base64EncodedKey' }
+})
+
+// Scroll utility
+async function * scrollSearch (params) {
+  let response = await client.search(params)
+
+  while (true) {
+    const sourceHits = response.hits.hits
+
+    if (sourceHits.length === 0) {
+      break
+    }
+
+    for (const hit of sourceHits) {
+      yield hit
+    }
+
+    if (!response._scroll_id) {
+      break
+    }
+
+    response = await client.scroll({
+      scroll_id: response._scroll_id,
+      scroll: params.scroll
+    })
+  }
+}
+
+async function run () {
+  await client.bulk({
+    refresh: true,
+    operations: [
+      { index: { _index: 'game-of-thrones' } },
+      {
+        character: 'Ned Stark',
+        quote: 'Winter is coming.'
+      },
+
+      { index: { _index: 'game-of-thrones' } },
+      {
+        character: 'Daenerys Targaryen',
+        quote: 'I am the blood of the dragon.'
+      },
+
+      { index: { _index: 'game-of-thrones' } },
+      {
+        character: 'Tyrion Lannister',
+        quote: 'A mind needs books like a sword needs a whetstone.'
+      }
+    ]
+  })
+
+  const params = {
+    index: 'game-of-thrones',
+    scroll: '30s',
+    size: 1,
+    _source: ['quote'],
+    query: {
+      match_all: {}
+    }
+  }
+
+  for await (const hit of scrollSearch(params)) {
+    console.log(hit._source)
+  }
+}
+
+run().catch(console.log)
+```
+