title: How can I get the index from the elasticsearch highlight?
body: <p>How can I get the index from the elasticsearch highlight?
  (index is array index. 
  value = ["a", "a b", "a b c", "a b c d", "a b c d e", "a b c d e f"]. 
  value[4] is "a b c d e".)</p>
  
  <p>Elasticsearch version is 6.4.3</p>
  
  <p>create document and search with highlight
  (First create a Document and apply highlighting to search.)</p>
  
  <pre><code>    post noritest/doc
      {
        "name": ["na", "nb", "nc", "nd", "ne", "nf"],
        "value": ["a", "a b", "a b c", "a b c d", "a b c d e", "a b c d e f"]
      }
  
      get noritest/_search
      {
        "query": {
          "match": {
            "value": "e"
          }
        },
        "highlight" : {
  
              "no_match_size": 150 ,
              "require_field_match": "false", 
              "pre_tags" : ["&lt;em&gt;"], "post_tags" : ["&lt;/em&gt;"],
              "fragment_size" : 150,
  
              "fields" : {
                  "value": {}
              }
          }
      }
  </code></pre>
  
  <p>result is 
  (I want to get the index of the element in the result. However, the index of the element is not included in the result.)</p>
  
  <pre><code>{
    "took": 0,
    "timed_out": false,
    "_shards": {
      "total": 1,
      "successful": 1,
      "skipped": 0,
      "failed": 0
    },
    "hits": {
      "total": 1,
      "max_score": 0.39556286,
      "hits": [
        {
          "_index": "noritest",
          "_type": "doc",
          "_id": "wj_5jWwBGmBhVrTXpU",
          "_score": 0.39556286,
          "_source": {
            "name": [
              "na",
              "nb",
              "nc",
              "nd",
              "ne",
              "nf"
            ],
            "value": [
              "a",
              "a b",
              "a b c",
              "a b c d",
              "a b c d e",
              "a b c d e f"
            ]
          },
          "highlight": {
            "value": [
              "a b c d &lt;em&gt;e&lt;/em&gt;",
              "a b c d &lt;em&gt;e&lt;/em&gt; f"
            ]
          }
        }
      ]
    }
  }
  </code></pre>
  
  <p>I want result is (example)</p>
  
  <pre><code>{
    "took": 0,
    "timed_out": false,
    "_shards": {
      "total": 1,
      "successful": 1,
      "skipped": 0,
      "failed": 0
    },
    "hits": {
      "total": 1,
      "max_score": 0.39556286,
      "hits": [
        {
          "_index": "noritest",
          "_type": "doc",
          "_id": "wj_5jWwBGmBhVrTXpU",
          "_score": 0.39556286,
          "_source": {
            "name": [
              "na",
              "nb",
              "nc",
              "nd",
              "ne",
              "nf"
            ],
            "value": [
              "a",
              "a b",
              "a b c",
              "a b c d",
              "a b c d e",
              "a b c d e f"
            ]
          },
          "highlight": {
            "value": [
              "a b c d &lt;em&gt;e&lt;/em&gt;",
              "a b c d &lt;em&gt;e&lt;/em&gt; f"
            ],
            "value.index": [
              4, 5
            ]
          }
        }
      ]
    }
  }
  </code></pre>
  
  <p>Help me..</p>