title: Set null dates on Google Chart Timeline
body: <p>Im trying to create a Timeline chart using Google Chart API. However the problem is I can't handle null dates on specific rows. </p>
  
  <p>How do you hide rows that have null Start or End dates? </p>
  
  <pre><code>google.charts.load("current", {packages:["timeline"]});
  google.charts.setOnLoadCallback(drawChart);
  
  function drawChart() {
      var container = document.getElementById('timeline');
      var chart = new google.visualization.Timeline(container);
      google.visualization.events.addListener(chart, 'error', errorHandler); 
      var dataTable = new google.visualization.DataTable();
      dataTable.addColumn({ type: 'string', id: 'Role' });
      dataTable.addColumn({ type: 'string', id: 'Name' });
      dataTable.addColumn({ type: 'date', id: 'Start' });
      dataTable.addColumn({ type: 'date', id: 'End' });
  
      dataTable.addRows([         
          [ 
              'NTC', 
              'NTC', 
              new Date('07/05/2016'),
              new Date('07/06/2016'),   
          ],
          [ 
              'Briefing Meeting',
              'Baseline',
              new Date('07/07/2016'),
              new Date('07/06/2016'),   
          ],
          [ 
              'Concept Design', 
              'Baseline',     
              new Date('07/05/2016'),
              new Date('07/06/2016'),   
          ],
          [ 
              'Concept Design', 
              'Forecast',     
              new Date('07/05/2016'),
              new Date('07/06/2016'),   
          ],
          [ 
              'Concept Design', 
              'Actual',     
              new Date('07/05/2016'),
              new Date('07/06/2016'),   
          ],
          [ 
              'Detail Design', 
              'Baseline', 
              new Date('07/05/2016'),
              new Date('07/06/2016'),   
          ],
          [ 
              'Detail Design', 
              'Forecast', 
              new Date('07/05/2016'),
              new Date('07/06/2016'),   
          ],
          [ 
              'Detail Design', 
              'Actual', 
              new Date('07/05/2016'),
              new Date(),   
          ],
      ]);
  
      var colors = [];
      var colorMap = {
          Baseline: '#425cfb',
          Forecast: '#f8ac08',
          Actual: '#06af90',
          NTC: '#1b9e2e'
      }
  
      for (var i = 0; i &lt; dataTable.getNumberOfRows(); i++) {
          colors.push(colorMap[dataTable.getValue(i, 1)]);
      }  
  
      var options = {
          colors: colors,
          timeline: {
              showBarLabels: false, 
              groupByRowLabel: true,
  
              // rowLabelStyle: {fontName: 'Helvetica', fontSize: 24, color: '#603913'},
              barLabelStyle: { fontName: 'Garamond', fontSize: 6 },
          },
  
          interpolateNulls: true,
      };
  }
  </code></pre>
  
  <p>It displays invalid datetime if I set new Date(0), Is there a workaround here?</p>