Using a function to return a value on a plotLine [HighCharts] : <p>I want to return a value in form of a plotLine in my chart.</p>

<pre><code>plotLines: [{
                  color: 'red',
                  value: resp.data.res0.map(function(a){
                    sum += parseInt(a[1]);
                    return sum;
                  }),
                  width: '1',
                  zIndex: 2
                }]
              },
</code></pre>

<p>The value of sum here is not that important, just that it is a number. But I am not sure how I am supposed to render it to the chart. The response in a[1] is JSON.</p>
