Jesus sucks

backend/frontend/node_modules/@restart/hooks/esm/useMutationObserver.js

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+import useCustomEffect from './useCustomEffect';
+import { dequal } from 'dequal';
+import useImmediateUpdateEffect from './useImmediateUpdateEffect';
+import useEventCallback from './useEventCallback';
+import { useState } from 'react';
+function isDepsEqual([nextElement, nextConfig], [prevElement, prevConfig]) {
+  return nextElement === prevElement && dequal(nextConfig, prevConfig);
+}
+
+/**
+ * Observe mutations on a DOM node or tree of DOM nodes.
+ * Depends on the `MutationObserver` api.
+ *
+ * ```tsx
+ * const [element, attachRef] = useCallbackRef(null);
+ *
+ * useMutationObserver(element, { subtree: true }, (records) => {
+ *
+ * });
+ *
+ * return (
+ *   <div ref={attachRef} />
+ * )
+ * ```
+ *
+ * @param element The DOM element to observe
+ * @param config The observer configuration
+ * @param callback A callback fired when a mutation occurs
+ */
+
+/**
+ * Observe mutations on a DOM node or tree of DOM nodes.
+ * use a `MutationObserver` and return records as the are received.
+ *
+ * ```tsx
+ * const [element, attachRef] = useCallbackRef(null);
+ *
+ * const records = useMutationObserver(element, { subtree: true });
+ *
+ * return (
+ *   <div ref={attachRef} />
+ * )
+ * ```
+ *
+ * @param element The DOM element to observe
+ * @param config The observer configuration
+ */
+
+function useMutationObserver(element, config, callback) {
+  const [records, setRecords] = useState(null);
+  const handler = useEventCallback(callback || setRecords);
+  useCustomEffect(() => {
+    if (!element) return;
+
+    // The behavior around reusing mutation observers is confusing
+    // observing again _should_ disable the last listener but doesn't
+    // seem to always be the case, maybe just in JSDOM? In any case the cost
+    // to redeclaring it is gonna be fairly low anyway, so make it simple
+    const observer = new MutationObserver(handler);
+    observer.observe(element, config);
+    return () => {
+      observer.disconnect();
+    };
+  }, [element, config], {
+    isEqual: isDepsEqual,
+    // Intentionally done in render, otherwise observer will miss any
+    // changes made to the DOM during this update
+    effectHook: useImmediateUpdateEffect
+  });
+  return callback ? void 0 : records || [];
+}
+export default useMutationObserver;