title: Google Chart ticks not displaying at all
body: <p>I have a problem with the vaxis.ticks option in google charts.</p>
  
  <p>My code does work and the chart is correct, but the strings in the ticks array are ignored and the initial numbers are displaying. No errors or warnings.</p>
  
  <p>I cant seem to find a solution for this problem.</p>
  
  <pre><code>$.ajax({
      url: '/api/chart/eta/lane/45',
      dataType: 'json'
  }).done(function (response) {
      var array = [];
      var ticks = [];
      array.push(['Time', 'line 1', 'line 2', 'line 3', 'line 4']);
      $.each(response, function (key, row) {
          array.push([new Date(row[0]), row[1], row[2], row[3], row[4]]);
          if(row[1])
              ticks.push({v: row[1], f: secondsToTime(row[1])});
          if(row[2])
              ticks.push({v: row[2], f: secondsToTime(row[2])});
          if(row[3])
              ticks.push({v: row[3], f: secondsToTime(row[3])});
          if(row[4])
              ticks.push({v: row[4], f: secondsToTime(row[4])});
      });
      google.charts.load('current', {'packages': ['line']});
      google.charts.setOnLoadCallback(drawChart);
      function drawChart() {
  
          var datatable = google.visualization.arrayToDataTable(array);
  
          var options = {
              width: 1000,
              height: 800,
              legend: {position: 'none'},
              hAxis: {
                  format: 'd.M.yyyy H:mm'
              },
              vAxis: {
                  title: "Δ ETA",
                  ticks: ticks
              }
          };
  
          var container = document.getElementById('chart');
          var chart = new google.charts.Line(container);
  
          chart.draw(datatable, google.charts.Line.convertOptions(options));
      }
  });
  
  function secondsToTime(seconds) {
      var isNegative = false;
      if(seconds &lt; 0) {
          seconds = Math.abs(seconds);
          isNegative = true;
      }
      return (isNegative ? '-' : '') + Math.floor(seconds / 3600) + ':' + Math.floor((seconds%3600) / 60);
  }
  </code></pre>
  
  <p>Example AJAX response:</p>
  
  <pre><code>[
      ["2018-07-25 17:09:24",311,4490,null,-10994],
      ["2018-07-25 17:16:20",364,4543,null,-11047],
      ["2018-07-25 17:19:29",412,4591,null,-11095],
      ["2018-07-25 17:21:25",528,4707,null,-11211],
      ["2018-07-25 17:21:43",546,4725,null,-11229],
      ["2018-07-25 17:22:01",564,4743,null,-11247],
      ["2018-07-25 17:22:18",581,4760,null,-11264],
      ["2018-07-25 17:22:38",601,4780,null,-11284],
      ["2018-07-25 17:22:57",620,4799,null,-11303],
      ["2018-07-25 17:23:17",640,4819,null,-11323],
      ["2018-07-25 17:23:36",659,null,5573,-11342],
      ["2018-07-25 17:23:56",616,null,5530,-11299],
      ["2018-07-25 17:28:02",862,null,5776,-11545]
  ]
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/2n2Rg.jpg" rel="nofollow noreferrer">Result</a></p>