Question

我在带有打字稿的项目中使用了这个ResizeObserver钩子


const useResizeObserver = () => {
  const [entry, setEntry] = useState<ResizeObserverEntry>();
  const [node, setNode] = useState<Element | null>(null);
  const observer = useRef<ResizeObserver | null>(null);

  const disconnect = useCallback(() => {
    const { current } = observer;
    if (current) {
      current.disconnect();
    }
  }, []);

  const observe = useCallback(() => {
    observer.current = new ResizeObserver(([entry1]) => setEntry(entry1));
    if (node) {
      observer.current.observe(node);
    }
  }, [node]);

  useLayoutEffect(() => {
    observe();
    return () => disconnect();
  }, [disconnect, observe]);

  return [setNode, entry];
};

const [node, entry] = useResizeObserver();
<div ref={node}>content</div>

当我在组件中使用此挂钩时，出现此错误

已修复帮助

Answer 1

您将返回# >>> conda initialize >>> # !! Contents within this block are managed by 'conda init' !! # these should already be in the PATH, but re-adding them wont hurt... export PATH="/bin:/usr/bin:/sbin:/usr/sbin:$PATH" # add other directories to the PATH here remembering to append (previous) PATH at the end PATH="/Users/arif/Library/Python/2.7/bin:$PATH" PATH="/usr/local/opt/ruby/bin:$PATH" PATH="/Library/Frameworks/Python.framework/Versions/3.8/bin:$PATH" PATH="/Applications/Postgres.app/Contents/Versions/latest/bin:$PATH" echo “source /usr/local/bin/virtualenvwrapper.sh” >> ~/.bash_profilesource /usr/local/bin/virtualenvwrapper.sh作为return数组中的第一个元素，并尝试将其用作TableHeader setNode。

ref不能用作setNode，请参见here，了解如何使用裁判

Answer 2

我发现问题出在我们混合数组[setNode, entry]时来自打字稿推断为联合类型。因此，为了解决此问题，您只需将其设置为固定返回数组，如下所示：

return [setNode, entry] as const;

注意：仅在v3.4 https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-4.html#const-assertions

中具有此const断言

如何在自定义钩子中修复打字稿错误

2 个答案: