Shashank,
Slider methods are accessible within the actual slider element and not the options of slider that you pass to StockChart. As mentioned in documentation stockChart.navigator.slider.set('minimum', new Date(2018, 01, 01));
should work fine in your case.
If you are still facing issue, kindly share sample project reproducing the issue you are facing & share it with us over Google-Drive or Onedrive along with sample / dummy data so that we can run it locally to debug at our end to understand the use-case better and help you resolve.
—
Vishwas R
Team CanvasJS