title: Angular 4:PrimeNg DoughnutChart dynamic data issue.
body: <p>I have recently been working on primeng charts, and I am using DoughnutChart provided by PrimeNG. I want to pass a number value stored in a variable as data in the ts file for this chart, but it will not show anything in the UI,where as if data is static it works absolutely fine.This is the code for the same:</p>
  
  <p><strong>1.)Working one:-</strong></p>
  
  <pre><code>this.invoicedata = {
              labels: ['InvoiceQty', 'TotalQty'],
              datasets: [
                  {
                      data: [50, 50],
                      backgroundColor: [
                          "#ff9800",
                          "#ffffff",
  
                      ],
                      hoverBackgroundColor: [
                          "#ff9800",
                          "#ffffff",
  
                      ]
                  }]
          }
  </code></pre>
  
  <p><strong>2.)Non-working one:-</strong></p>
  
  <pre><code>  this.invoicedata = {
                  labels: ['InvoiceQty', 'TotalQty'],
                  datasets: [
                      {
                          data: [this.pICompletionPercentage, this.PIPendingpercent],
                          backgroundColor: [
                              "#ff9800",
                              "#ffffff",
  
                          ],
                          hoverBackgroundColor: [
                              "#ff9800",
                              "#ffffff",
  
                          ]
                      }]
              }
  </code></pre>
  
  <p>This is HTML for the same:-</p>
  
  <pre><code> &lt;div class="row"&gt;
                                  &lt;p-chart type="doughnut" [data]="invoicedata" width="150px"&gt;&lt;/p-chart&gt;
                                  &lt;p class="text-center"&gt;Invoiced- {{pICompletionPercentage}}%&lt;/p&gt;
                              &lt;/div&gt;
  </code></pre>