Instant search error on beforeWidgetInitialization hook

[Trio-web]

Hi,

I'm try to customize page result using beforeWidgetInitialization hook as described here:

https://www.algolia.com/doc/integration/magento-2/customize/instant-search-page/?client=php#product-results-or-hits

but if I use code snippet suggested, a javascript error is generated when callbackTransform(items) function is called.
Error is this:

If I comment line:

items = callbackTransform(items);

my code works, but callbacks on items are not called.

Magento 2.4.6-p2
Algolia_AlgoliaSearch 3.10.6
Algolia_CustomAlgolia 1.2.2