function getParent(elemSelector, parentSelector) {
var elem = document.querySelector(elemSelector);
var parents = document.querySelectorAll(parentSelector);
for (var i = 0; i < parents.length; i++) {
var parent = parents[i];
if (parent.contains(elem)) {
return parent;
}
}
return null;
}
var result = getParent(
'.product__shopcard-btn',
'.product'
);
console.log(result);