i want to do something similar to what you have achieved , i want to load the contracts module(account.analytic.account) so i can get the contract reference and display it on the receipt. The tricky part is the only way to link the product in the point of sale back to  their contract is : product.product > account.analytic.invoice.line > account.analytic.account , so is there any way i can achieve this ?

Hi Thanks and wish you the same...

I think Yenthe's method might work... sure you can inherit a js, (i.e) you have to extend instance/model etc...

I had inherited JS of List view Widget of Journal Items, it worked fine for me... you can have a look at it ..

 
/*
   [Inherited]: account_move_line_quickadd.js
                To Remove default values for (Journal & Period)
*/
    instance.web.account.QuickAddListView = instance.web.account.QuickAddListView.extend(
    {
        start:function(){
            var tmp = this._super.apply(this, arguments);
            var self = this;
            
            var mod = new instance.web.Model("account.move.line", self.dataset.context, self.dataset.domain);
            mod.call("default_get", [['journal_id','period_id'],self.dataset.context]).then(function(result) {
                self.current_period = null;
                self.current_journal = null;
            });
            return tmp;
          },
    });
};

So  I think you may have to try some thing like this for the model extention also ...

If it didnt work out then worst case, you have to create your own custom receipt...