title: How can I search without knowing the field in Elasticsearch
body: <p>I have about 100k documents and they look something like this:</p>
  
  <pre><code>{
    "news": "abc",
    "createdAt": 1527786360574,
    "id": "fc554a1d-64f4-11e8-5a54-fbcd7712f7bf",
    "location": "東京都 Japan",
    "title": "Something happened",
    "url": "url-of-the-news",
    "userId": "fc515a1c-69g4-1ie8-9a54-ftcd775ff7bf",
    "username": "stevemao",
    "attributes": []
  }
  </code></pre>
  
  <p>On the frontend there's only one text field and I use it to search for anything (including fuzziness). </p>
  
  <p>EG: if the input is <code>"japan"</code> I'm expecting the document above to return. Same as <code>"abc"</code> since it's the news. If there's attributes I can search that too.</p>
  
  <p>I don't know the field value for the search. How should I index the documents and what field should I specify when searching them.</p>