Filter the sample catalog
The fictional example contains an items array with three products. Run $.items[?@.stock > 0].name to return Desk Lamp at $['items'][0]['name']. Travel Mug has stock 0; Notebook has stock null. Neither satisfies the positive-stock condition.
Input changes clear the old results. Invalid JSON, an invalid expression and a valid expression with no matches have different outcomes. An empty result is exported as an empty array, not replaced with example data.
$.items[?@.stock > 0].name