Can we extends the Categories. Js

Yes you can

return _.extend(Categories, {

// do some work

});

I wanted to do some changes in makenavigationTab??if make any changes in that I am not getting additionfields array in category object

Make sure to call this after your changes inside the code block

this.application.trigger('Configuration.navigationData');

Where I need to write this snippet

In my case I need to make changes in

addToNavigationTabs

and

makeNavigationTab

. This is the code block I modified and was it working perfectly.

if (index !== -1) {

self.fetchCategoriesToExclude().then(function(response) {

var tabs = self.makeNavigationTab(categories, response.data.categories);

// navigationData.splice(index, 1);

_.each(tabs, function(tab, position) {

navigationData.splice(index + position, 0, tab);

});

self.application.trigger('Configuration.navigationData');

});

}

I want to add custom field data to tab section

Yes you can. Create a service to fetch the data from custom field and modify the methods I mentioned above as per your needs.

if you are just adding a simple link that redirect to a landing page, then you can simply add it in the configuration section