Accordion - Handle auto-open if inner element is linked to

components/Accordion.jsx

@@ -1,10 +1,57 @@
-import React from "react";
+import React, { useRef, useEffect } from "react";
 
-const Accordion = ({ children, title = "More" }) => (
-  <details>
-    <summary>{title}</summary>
+const Accordion = ({ children, title = "More" }) => {
+  const detailsRef = useRef(null);
+  const summaryRef = useRef(null);
+
+  function openAccordionOnHash() {
+    const hash = location.hash.substring(1);
+    if (hash.length === 0) {
+      return;
+    }
+    let targetElement;
+    targetElement = document.getElementById(hash);
+    if (targetElement === null) {
+      return;
+    }
+
+    // 1. If target is within current details element
+    const detailsElement = detailsRef.current;
+    const summaryElement = summaryRef.current;
+    if (
+      detailsElement !== null &&
+      summaryElement.current !== null &&
+      detailsElement.contains(targetElement)
+    ) {
+      // 2. and it is not open,
+      if (!detailsElement.open) {
+        // 3. Then open it
+        detailsElement.open = true;
+        // 4. and scroll into view, focus on summary
+        summaryElement.focus();
+        targetElement.scrollIntoView({ behavior: "smooth", block: "center" });
+      }
+    }
+  }
+
+  useEffect(() => {
+    // 1. Add event listener for future hash changes
+    window.addEventListener("hashchange", openAccordionOnHash);
+    // 2. Do it anyway now if initial url has hash
+    openAccordionOnHash()
+
+    // Cleanup - remove listener
+    return () => {
+      window.removeEventListener("hashchange", openAccordionOnHash);
+    };
+  }, []);
+
+  return (
+    <details ref={detailsRef}>
+      <summary ref={summaryRef}>{title}</summary>
       {children}
     </details>
   );
+};
 
 export default Accordion;