Watch for removal of a node from the document body

example.js

var node = document.createElement('div');
node.innerHTML = "you know. hwhatever";
document.body.insertBefore(node, document.body.firstElementChild);

var subnode1 = document.createElement('div');
subnode1.innerHTML = "you know. hwhatever again (1)";
node.appendChild(subnode1);

var subnode2 = document.createElement('div');
subnode2.innerHTML = "you know. hwhatever again (2)";
node.appendChild(subnode2);

var mo = new MutationObserver((events,o) => {
    for (var i = 0; i < events.length; i++) {
        for (var j = 0; j < events[i].removedNodes.length; j++) {
            console.log('caught removal event for', events[i].removedNodes[j]);
        }
    }
});
mo.observe(document.body, {subtree: true, childList: true});

node.removeChild(subnode1);
node.removeChild(subnode2);

setTimeout(() => {
    mo.disconnect();
}, 1000);