MutationObserver回调函数中mutationList的TypeScript类型是什么？

在TypeScript中，MutationObserver回调函数里的mutationList对应的类型是**MutationRecord[]**，即MutationRecord对象的数组。

每个mutation项的类型MutationRecord包含DOM变更的完整信息，比如变更类型（type）、被修改的属性名（attributeName）、新增/移除的节点集合等，完全匹配你代码中对mutation的判断逻辑。

给回调函数显式添加类型标注后，代码类型会更清晰，还能获得TypeScript的类型校验和代码提示：

const targetNode = document.getElementById("some-id");

const config = { attributes: true, childList: true, subtree: true };

const callback = (mutationList: MutationRecord[], observer: MutationObserver) => {
  for (const mutation of mutationList) {
    if (mutation.type === "childList") {
      console.log("A child node has been added or removed.");
    } else if (mutation.type === "attributes") {
      console.log(`The ${mutation.attributeName} attribute was modified.`);
    }
  }
};

const observer = new MutationObserver(callback);

observer.observe(targetNode, config);

内容的提问来源于stack exchange，提问作者Anjan Talatam