You can leverage the Capability APIs into your visualization by loading the qlik JavaScript module, the same module used when building websites that includes Qlik Sense objects and calls.
Warning noteDo not use the js/ prefix when loading the qlik JavaScript module in your visualization. This may cause unexpected behavior of Qlik Sense.
The below example comes from the Toolbar code example delivered with your Qlik Sense installation.
Example
define(["jquery",
//mashup and extension interface
"qlik"], function($, qlik) {