title: Openlayers 3 - add variable to ol.layer.Vector in a second time
body: <p>in my project I define many var, including this one in example:</p>
  <pre><code>var lyr_Confini = new ol.layer.Vector({
                  declutter: true,
                  source: jsonSource_Confini, 
                  style: style_Confini,
                  interactive: true,
                  title: 'Confini'
              });
  </code></pre>
  <p>In a second time, or in another file called later in the index.html, I would like to add a variable in this <code>ol.layer.Vector</code> without overwriting the other variables like:</p>
  <pre><code>permalink: 'example',
  </code></pre>
  <p>to have this example in the end:</p>
  <pre><code>var lyr_Confini = new ol.layer.Vector({
                      declutter: true,
                      source: jsonSource_Confini, 
                      style: style_Confini,
                      interactive: true,
                      title: 'Confini',
                      permalink: 'example',
                  });
  </code></pre>
  <p>How can I do?
  Thanks</p>