From 446ec1bbe5b0e57c125e60343a7c5c084499959b Mon Sep 17 00:00:00 2001
From: Aleksandr Gumroian <aleksandr.gumroian@nic.cz>
Date: Mon, 16 Sep 2024 17:59:21 +0200
Subject: [PATCH] Refactor Modal component to use useFocusTrap hook

---
 src/bootstrap/Modal.js | 15 +++++++++------
 src/utils/hooks.js     | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/src/bootstrap/Modal.js b/src/bootstrap/Modal.js
index aee202b..87f1cd6 100644
--- a/src/bootstrap/Modal.js
+++ b/src/bootstrap/Modal.js
@@ -9,7 +9,7 @@ import React, { useRef, useEffect } from "react";
 
 import PropTypes from "prop-types";
 
-import { useClickOutside } from "../utils/hooks";
+import { useClickOutside, useFocusTrap } from "../utils/hooks";
 import Portal from "../utils/Portal";
 import "./Modal.css";
 
@@ -29,10 +29,11 @@ Modal.propTypes = {
 };
 
 export function Modal({ shown, setShown, scrollable, size, children }) {
-    const dialogRef = useRef();
+    const modalRef = useRef();
     let modalSize = "modal-";
 
-    useClickOutside(dialogRef, () => setShown(false));
+    useClickOutside(modalRef, () => setShown(false));
+    useFocusTrap(modalRef);
 
     useEffect(() => {
         const handleEsc = (event) => {
@@ -45,7 +46,7 @@ export function Modal({ shown, setShown, scrollable, size, children }) {
         return () => {
             window.removeEventListener("keydown", handleEsc);
         };
-    }, [setShown]);
+    }, [shown]);
 
     switch (size) {
         case "sm":
@@ -65,11 +66,13 @@ export function Modal({ shown, setShown, scrollable, size, children }) {
     return (
         <Portal containerId="modal-container">
             <div
+                ref={modalRef}
                 className={`modal fade ${shown ? "show" : ""}`.trim()}
                 role="dialog"
+                aria-modal="true"
+                aria-labelledby="modal-title"
             >
                 <div
-                    ref={dialogRef}
                     className={`${modalSize.trim()} modal-dialog modal-dialog-centered ${
                         scrollable ? "modal-dialog-scrollable" : ""
                     }`.trim()}
@@ -90,7 +93,7 @@ ModalHeader.propTypes = {
 export function ModalHeader({ setShown, title }) {
     return (
         <div className="modal-header">
-            <h5 className="modal-title">{title}</h5>
+            <h1 className="modal-title fs-5">{title}</h1>
             <button
                 type="button"
                 className="btn-close"
diff --git a/src/utils/hooks.js b/src/utils/hooks.js
index db0c465..8e92ca3 100644
--- a/src/utils/hooks.js
+++ b/src/utils/hooks.js
@@ -40,3 +40,41 @@ export function useClickOutside(element, callback) {
         };
     });
 }
+
+/* Trap focus inside modal. */
+export function useFocusTrap(modalRef) {
+    useEffect(() => {
+        if (shown) {
+            const modal = modalRef.current;
+            const focusableElements = modal.querySelectorAll(
+                'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
+            );
+            const firstElement = focusableElements[0];
+            const lastElement = focusableElements[focusableElements.length - 1];
+
+            const handleTab = (event) => {
+                if (event.key === "Tab") {
+                    if (event.shiftKey) {
+                        if (document.activeElement === firstElement) {
+                            lastElement.focus();
+                            event.preventDefault();
+                        }
+                    } else {
+                        if (document.activeElement === lastElement) {
+                            firstElement.focus();
+                            event.preventDefault();
+                        }
+                    }
+                }
+            };
+
+            modal.addEventListener("keydown", handleTab);
+
+            firstElement.focus();
+
+            return () => {
+                modal.removeEventListener("keydown", handleTab);
+            };
+        }
+    }, [shown]);
+}