title: Why should I create a json to save a document from Mongoose + MongoDB + Node.JS?
body: <p>Consider, Mongoose schema:</p>
  
  <pre><code>var schema_obj = new Schema({
      field1: String,
      field2: String, .........
  });
  </code></pre>
  
  <p>JSON document, like:</p>
  
  <pre><code>var json_obj = {
  field1: 'value', 
  field2 : 'val2', 
  ............
  };
  </code></pre>
  
  <p>For saving I call method, like</p>
  
  <pre><code>var Model_obj = mongoose.model('model_name', schema_object);
  var document_obj = new Model_obj(json_obj);
  document_obj.save(function(err,data){/*some logic after save*/});
  </code></pre>
  
  <p>Now my question is: Why should I create a <strong>json_obj</strong>. 
  When I already have a schema object in my hand, which already has all the fields (field1, field2). If I just want to give values for those fields why should I create json by writing all the field name again? </p>
  
  <p>If I have <em>n</em> number of fields this becomes a overhead to write all fields again. Is there any way to avoid this overhead?</p>
  
  <p>Something like I get a empty JSON object out of my defined mongoose schema, then just proceed by assigning only values?</p>