title: Elasticsearch Javascript Client Update not working
body: <p>I am using elasticsearch JavaScript client with nodejs (Typescript). The update query is not working as expected can any one help me on this </p>
  
  <p>My code is </p>
  
  <pre><code>const EsResponse = await esClient.update({
        index: "myindex",
        type: "mytype",
        id: "1",
        body: {
          // put the partial document under the `doc` key
          doc: {
            title: "Updated"
          }
        }
      });
  </code></pre>
  
  <p>And the response is </p>
  
  <pre><code>{
      "msg": "[invalid_type_name_exception] Document mapping type name can't start with '_', found: [_update]",
      "path": "/myindex/_update/1",
      "query": {
          "type": "mytype"
      },
      "body": "{\"doc\":{\"title\":\"Updated\"}}",
      "statusCode": 400,
      "response": "{\"error\":{\"root_cause\":[{\"type\":\"invalid_type_name_exception\",\"reason\":\"Document mapping type name can't start with '_', found: [_update]\"}],\"type\":\"invalid_type_name_exception\",\"reason\":\"Document mapping type name can't start with '_', found: [_update]\"},\"status\":400}"
  }
  </code></pre>
  
  <p>My <code>package.json</code> file is </p>
  
  <pre><code>{
    "name": "backend",
    "version": "1.0.0",
    "description": "The backend system",
    "main": "dist/index.js",
    "scripts": {
      "prebuild": "tslint -c tslint.json -p tsconfig.json --fix",
      "build": "tsc",
      "prestart": "npm run build",
      "start": "nodemon .",
      "test": "echo \"Error: no test specified\" &amp;&amp; exit 1"
    },
    "author": "Jagadeesh Kumar CK",
    "license": "ISC",
    "dependencies": {
      "@types/body-parser": "^1.17.1",
      "@types/cors": "^2.8.6",
      "cors": "^2.8.5",
      "elasticsearch": "^16.5.0",
      "express": "^4.17.1",
      "ts-node": "^8.5.2"
    },
    "devDependencies": {
      "@types/elasticsearch": "^5.0.36",
      "@types/express": "^4.17.2",
      "@types/node": "^12.12.12",
      "tslint": "^5.20.1",
      "typescript": "^3.7.2"
    }
  }
  </code></pre>
  
  <p>My elastic search version is 6.3</p>