Form primitives, keyboard-operable comboboxes, dialog focus, route states

Accessibility work on the UI layer, all of it rooted in one structural gap: there were no form primitives, so every field was hand-assembled and every field got the same details wrong. Form primitives - components/ui/Field.tsx (Field/TextField/SelectField/TextareaField) and Button.tsx. Field generates the control id with useId and derives htmlFor from it, which is what makes the association impossible to omit rather than merely conventional. - 92 labels existed, 4 used htmlFor, and no input carried an id at all: a screen reader announced an unnamed edit box and clicking a label focused nothing. Now every label resolves to its control (0 unassociated), and the input class chain that appeared verbatim 85 times appears zero times. - Field also takes a render prop, so Lookup, CountryPicker and Picklist get the same wiring instead of a second, partial solution. - SearchInput replaces three hand-rolled copies of the icon-in-a-box search whose input had only a placeholder — not a label — and killed its own focus ring with outline-none and nothing in its place. - Toggle groups (workdays, reorg change type) became fieldsets with aria-pressed; colour alone was carrying the selected state. Comboboxes - Lookup and CountryPicker were text inputs with a div of clickable buttons underneath: typeable, but no keyboard path to a result and nothing telling a screen reader a list had appeared. Both now carry role=combobox, aria-expanded/controls/activedescendant and listbox semantics, with arrow keys, Enter and Escape. Escape stops propagation, or it would close the surrounding dialog along with the dropdown. Dialogs - useDialogFocus centralises what Modal and SlideOver each owed the keyboard and neither provided beyond Escape: focus into the dialog on open, Tab and Shift+Tab cycling within it, focus restored to the trigger on close. - SlideOver stays mounted for its transition, and aria-hidden does not remove anything from the tab order — so every closed panel was leaving invisible tab stops at the end of the page. `inert` fixes that. Route states - loading.tsx, error.tsx, not-found.tsx and global-error.tsx. Every page in the (app) group is server-rendered per request, so without loading.tsx a navigation showed nothing at all until the server answered, and a render error dropped the user on Next's own screen with no way back. Tests - 22 component tests (vitest jsdom project). Two of them found limits of the environment rather than of the code: jsdom implements neither `inert` nor scrollIntoView, so the inert test asserts the attribute and the missing scrollIntoView — which was taking the whole render down from inside an effect — is stubbed in the setup file.
2026-07-25 13:10:52 +02:00
parent 4be5f2264e
commit d9367a8ce4
44 changed files with 1770 additions and 1127 deletions
--- a/components/ui/useDialogFocus.ts
+++ b/components/ui/useDialogFocus.ts
@@ -0,0 +1,78 @@
+"use client";
+
+import { useEffect, useRef, type RefObject } from "react";
+
+// Everything a dialog owes the keyboard, in one place so Modal and SlideOver
+// cannot drift apart. Both previously handled only Escape: focus stayed on
+// whatever was behind the overlay, Tab walked straight out of the dialog into
+// the page underneath, and closing left focus on <body> — so the next Tab
+// started again from the top of the document.
+const FOCUSABLE = [
+  "a[href]",
+  "button:not([disabled])",
+  "input:not([disabled]):not([type='hidden'])",
+  "select:not([disabled])",
+  "textarea:not([disabled])",
+  "[tabindex]:not([tabindex='-1'])",
+].join(",");
+
+function focusableWithin(container: HTMLElement): HTMLElement[] {
+  return [...container.querySelectorAll<HTMLElement>(FOCUSABLE)].filter(
+    (el) => el.offsetParent !== null || el.getClientRects().length > 0
+  );
+}
+
+export function useDialogFocus(open: boolean, onClose: () => void, containerRef: RefObject<HTMLElement | null>) {
+  const restoreToRef = useRef<HTMLElement | null>(null);
+
+  useEffect(() => {
+    if (!open) return;
+    const container = containerRef.current;
+    restoreToRef.current = document.activeElement instanceof HTMLElement ? document.activeElement : null;
+
+    // First field rather than the close button: the point of opening these is
+    // to fill them in. autoFocus on a child wins, since it has already run.
+    if (container && !container.contains(document.activeElement)) {
+      const [first] = focusableWithin(container);
+      (first ?? container).focus();
+    }
+
+    function onKeyDown(e: KeyboardEvent) {
+      if (e.key === "Escape") {
+        onClose();
+        return;
+      }
+      if (e.key !== "Tab" || !container) return;
+
+      const focusable = focusableWithin(container);
+      if (focusable.length === 0) {
+        e.preventDefault();
+        return;
+      }
+      const first = focusable[0];
+      const last = focusable[focusable.length - 1];
+      const active = document.activeElement;
+
+      // Wrap around at both ends, and pull focus back in if it somehow
+      // escaped (a click on the backdrop, say).
+      if (!container.contains(active)) {
+        e.preventDefault();
+        (e.shiftKey ? last : first).focus();
+      } else if (e.shiftKey && active === first) {
+        e.preventDefault();
+        last.focus();
+      } else if (!e.shiftKey && active === last) {
+        e.preventDefault();
+        first.focus();
+      }
+    }
+
+    window.addEventListener("keydown", onKeyDown);
+    return () => {
+      window.removeEventListener("keydown", onKeyDown);
+      // Back to whatever opened the dialog, so the next Tab continues from
+      // there instead of restarting at the top of the page.
+      restoreToRef.current?.focus();
+    };
+  }, [open, onClose, containerRef]);
+}