Basically I need to some method overwrite/extend of following Js class.
magento/module-checkout/view/frontend/web/js/model/step-navigator.js
Overwrite of this class through requirejs working fine. But I need to extend one of method of this class. here is an example of overwrite requirejs-config.js
var config = { "map": { "*": { "Magento_Checkout/js/model/step-navigator": "SR_Checkout/js/model/step-navigator" } } };
How to extend some method of any model class in checkout.