[FIX] pos_cache: eval domain before sending it to server

Since changes made on 'product.product' model in rev: 30e4d89a
the domain is not represented as a string, but as a function, and that
leads to error as the javascript function is sent to the server instead
of a string representing a domain.

So we check the type of domain to see if we have to evaluate a function
or send the domain as a string

closes odoo/odoo#34453

Signed-off-by: pimodoo <pimodoo@users.noreply.github.com>

addons/pos_cache/static/src/js/pos_cache.js

@@ -15,22 +15,21 @@ models.PosModel = models.PosModel.extend({
             return model.model === "product.product";
         });
 
-        // Give both the fields and domain to pos_cache in the
-        // backend. This way we don't have to hardcode these
-        // values in the backend and they automatically stay in
-        // sync with whatever is defined (and maybe extended by
-        // other modules) in js.
-        var product_model = this.models[product_index];
-        var product_fields = product_model.fields;
-        var product_domain = product_model.domain;
+        var product_model = self.models[product_index];
 
         // We don't want to load product.product the normal
         // uncached way, so get rid of it.
         if (product_index !== -1) {
             this.models.splice(product_index, 1);
         }
-
         return posmodel_super.load_server_data.apply(this, arguments).then(function () {
+          // Give both the fields and domain to pos_cache in the
+          // backend. This way we don't have to hardcode these
+          // values in the backend and they automatically stay in
+          // sync with whatever is defined (and maybe extended by
+          // other modules) in js.
+          var product_fields =  typeof product_model.fields === 'function'  ? product_model.fields(self)  : product_model.fields;
+          var product_domain =  typeof product_model.domain === 'function'  ? product_model.domain(self)  : product_model.domain;
             var records = rpc.query({
                     model: 'pos.config',
                     method: 'get_products_from_cache',