We would like to avoid creating a new POS Order after payment if there is already another one open.

We already found the related part into the point of sale app.

addons/point_of_sale/static/src/js/models.js

exports.PosModel = Backbone.Model.extend({
...
on_removed_order: function(removed_order,index,reason){
...
else{ 
// when the order was automatically removed after completion, 
// or when we intentionally delete the only concurrent order 

// ----------- start replaced code
// this.add_new_order();
// ----------- end replaced code

// ----------- start new code
// select first order after we finish unless there are none left
if (order_list.length > 0)
    { this.set_order(order_list[index] || order_list[order_list.length -1]); 
    }
else{ 
    this.add_new_order();
    }
// ----------- end new code

Now we would like to create an odoo module (V13) which replaces the related part of models.js file of the point_of_sale app.

We already managed to create small modules addings additional attributes and views. But how can we replace js code from another App?