title: Cannot convert object to primitive value
body: <p>I post data to node server:</p>
  
  <pre><code>{
    "form_1": [{
      "resultName": "",
      "level": "",
      "unitOrder": "",
      "winner": "",
      "winnerOrder": "",
      "date": "1",
      "score": ""
    }],
    "form_2": [{
      "resultName": "",
      "level": "",
      "unitOrder": "",
      "winner": "",
      "winnerOrder": "",
      "date": "1",
      "score": ""
    }],
    "form_3": [{
      "resultName": "",
      "level": "",
      "unitOrder": "",
      "winner": "",
      "winnerOrder": "",
      "date": "1",
      "score": ""
    }]
  }
  </code></pre>
  
  <p>And I try to console.log the data in express server:</p>
  
  <pre><code>console.log(req.body)
  </code></pre>
  
  <p>but there comes the error:</p>
  
  <blockquote>
    <p>TypeError: Cannot convert object to primitive value</p>
  </blockquote>
  
  <p>I do not understand. so how can I get the data ?</p>