[рони]

maxim1978,
можно чуть покороче )))

window.addEventListener("load", function() {
            document
                .querySelectorAll(".item")
                .forEach(function(el, i) {
                    el.addEventListener("change", function(event) {
                        let height = event.target.checked ? (el.scrollHeight + "px") : "";
                        el.style.height = height;
                    });
                });

        });

или ещё покороче)))

window.addEventListener("load", function() {
            document
                .querySelector(".wrapper")
                .addEventListener("change", function(event) {
                        let el = event.target.closest(".item");
                        let height = event.target.checked ? (el.scrollHeight + "px") : "";
                        el.style.height = height;
                });
        });