Function trackMutations

packages/react-aria/src/tokenfield/useTokenField.ts:801–834

(element: Element)

// Tracks mutations to the DOM until the returned function is called,
// at which point the mutations are reverted.
function trackMutations(element: Element) {
  let mutations: MutationRecord[] = [];
  let observer = new MutationObserver(records => {
    mutations.push(...records);
  });

  observer.observe(element, {
    childList: true,
    subtree: true,
    characterData: true,
    characterDataOldValue: true
  });

  return () => {
    mutations.push(...observer.takeRecords());
    observer.disconnect();

    for (let record of mutations.reverse()) {
      switch (record.type) {
        case 'childList':
          for (let node of record.removedNodes) {
            record.target.insertBefore(node, record.nextSibling);
          }
          for (let node of record.addedNodes) {
            record.target.removeChild(node);
          }
          break;
        case 'characterData':
          record.target.nodeValue = record.oldValue;
          break;
      }
    }
  };
}