title: How to replace undefined values with empty string in an array object?
body: <p>Array object:</p>
  
  <pre><code> var jsonList= {
          "list": [{
              "COLUMN_NAME": "control_master_id",
              "REFERENCED_COLUMN_NAME": "control_master_id",
              "REFERENCED_TABLE_NAME": "tbi_controls_master",
              "TABLE_NAME": "tbi_widget_controls"
          }, {
              "COLUMN_NAME": "authorization_id",
              "REFERENCED_COLUMN_NAME": "authorization_id",
              "REFERENCED_TABLE_NAME": "tbi_authorization_master",
              "TABLE_NAME": "tbi_controls_master"
          }, {
              "COLUMN_NAME": undefined,
              "REFERENCED_COLUMN_NAME": undefined,
              "REFERENCED_TABLE_NAME": undefined,
              "TABLE_NAME": "tbi_widget_controls "
          }]
      }
  </code></pre>
  
  <p>Expected solution:</p>
  
  <pre><code>var jsonList={
      "list": [{
          "COLUMN_NAME": "control_master_id",
          "REFERENCED_COLUMN_NAME": "control_master_id",
          "REFERENCED_TABLE_NAME": "tbi_controls_master",
          "TABLE_NAME": "tbi_widget_controls"
      }, {
          "COLUMN_NAME": "authorization_id",
          "REFERENCED_COLUMN_NAME": "authorization_id",
          "REFERENCED_TABLE_NAME": "tbi_authorization_master",
          "TABLE_NAME": "tbi_controls_master"
      }, {
          "COLUMN_NAME": "",
          "REFERENCED_COLUMN_NAME": "",
          "REFERENCED_TABLE_NAME": "",
          "TABLE_NAME": "tbi_widget_controls "
      }]
  }
  </code></pre>
  
  <p>Is there any solution to do this using <a href="http://underscorejs.org/" rel="noreferrer">underscore.js</a>?Any ideas? Elegant solutions?</p>