Make the canvas keyboard-reachable + trap focus in dialogs #92

Merged
steve merged 2 commits from feat/canvas-a11y into main 2026-07-22 03:34:08 +00:00
2 changed files with 35 additions and 16 deletions
Showing only changes of commit 4b348dcbc0 - Show all commits
+23 -10
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@@ -1,5 +1,12 @@
import { useEffect, useRef, type ReactNode } from 'react'
// Tabbable controls inside the dialog, in DOM order. type="hidden" inputs are
// excluded — they'd match `input:not([disabled])` and, sitting at a boundary,
// break the wrap math. Hoisted out of the handler so it isn't rebuilt per Tab.
const FOCUSABLE_SELECTOR =
'a[href], button:not([disabled]), textarea:not([disabled]), ' +
'input:not([disabled]):not([type="hidden"]), select:not([disabled]), [tabindex]:not([tabindex="-1"])'
/**
* A centered modal dialog over a dimmed backdrop. Closes on Escape or a backdrop
* click, unless `busy` (a mutation is in flight) — then it stays put so the
@@ -33,13 +40,8 @@ export function Modal({
const opener = document.activeElement as HTMLElement | null
Review

🟠 focusable() selector includes input[type="hidden"], breaking tab trap boundary when hidden inputs are at modal edges

correctness, maintainability · flagged by 2 models

  • web/src/components/ui/Modal.tsx:40 — The focusable() selector uses input:not([disabled]), which includes input[type="hidden"]. Hidden inputs are not keyboard-focusable. If a modal ever places a hidden input at the start or end of its content (e.g., a form with a CSRF token), the focus trap’s boundary checks (active === first / active === last) will compare against the hidden input instead of the real last tabbable control. Tab (or Shift+Tab) from the actual last visible button…

🪰 Gadfly · advisory

🟠 **focusable() selector includes input[type="hidden"], breaking tab trap boundary when hidden inputs are at modal edges** _correctness, maintainability · flagged by 2 models_ - **`web/src/components/ui/Modal.tsx:40`** — The `focusable()` selector uses `input:not([disabled])`, which includes `input[type="hidden"]`. Hidden inputs are not keyboard-focusable. If a modal ever places a hidden input at the start or end of its content (e.g., a form with a CSRF token), the focus trap’s boundary checks (`active === first` / `active === last`) will compare against the hidden input instead of the real last tabbable control. Tab (or Shift+Tab) from the actual last visible button… <sub>🪰 Gadfly · advisory</sub>
card?.focus()
// The dialog's own focusable controls, in DOM order, skipping disabled ones.
const focusable = () =>
Array.from(
card?.querySelectorAll<HTMLElement>(
'a[href], button:not([disabled]), textarea:not([disabled]), input:not([disabled]), select:not([disabled]), [tabindex]:not([tabindex="-1"])',
) ?? [],
)
Array.from(card?.querySelectorAll<HTMLElement>(FOCUSABLE_SELECTOR) ?? [])
function onKey(e: KeyboardEvent) {
if (e.key === 'Escape' && !busyRef.current) {
@@ -47,9 +49,6 @@ export function Modal({
return
Review

🟠 Focus trap doesn't handle the focused element being removed from the DOM (e.g. ShareGardenModal's remove-share button), letting Tab escape the dialog

correctness · flagged by 1 model

  • web/src/components/ui/Modal.tsx:49 — The Tab-trap checks active === first/last/card but not the case where the previously-focused element was removed from the DOM (focus reverts to <body> per browser default). ShareGardenModal.tsx:117-127's per-share "✕ Remove" button lives inside the trapped dialog; activating it via keyboard removes it from the list, so the next Tab press finds document.activeElement === body, which matches none of the checked branches — no preventDefault() fires…

🪰 Gadfly · advisory

🟠 **Focus trap doesn't handle the focused element being removed from the DOM (e.g. ShareGardenModal's remove-share button), letting Tab escape the dialog** _correctness · flagged by 1 model_ - `web/src/components/ui/Modal.tsx:49` — The Tab-trap checks `active === first/last/card` but not the case where the previously-focused element was removed from the DOM (focus reverts to `<body>` per browser default). `ShareGardenModal.tsx:117-127`'s per-share "✕ Remove" button lives inside the trapped dialog; activating it via keyboard removes it from the list, so the next Tab press finds `document.activeElement === body`, which matches none of the checked branches — no `preventDefault()` fires… <sub>🪰 Gadfly · advisory</sub>
}
if (e.key !== 'Tab') return
// Trap Tab inside the dialog: wrap at the ends, and pull a stray focus
// (e.g. starting from the card itself) back to a real control. Without
// this, Tab walks straight out into the page behind the backdrop.
const items = focusable()
if (items.length === 0) {
e.preventDefault()
@@ -59,6 +58,15 @@ export function Modal({
const first = items[0]
const last = items[items.length - 1]
const active = document.activeElement
// If focus is NOT inside the dialog, pull it back in rather than let Tab
Outdated
Review

🟡 Focus trap falls through (Tab escapes) when activeElement is outside {first, last, card} — external/stolen focus isn't pulled back in

correctness, error-handling · flagged by 2 models

  • web/src/components/ui/Modal.tsx:61-68 — the Tab-wrap logic only fires when active === first (Shift), active === card (Shift), or active === last (non-Shift). If document.activeElement is none of those — e.g. focus escaped to <body> or an element behind the backdrop because something stole focus after mount, or focus landed on a [tabindex="-1"] child that isn't the card — neither branch executes, preventDefault is not called, and Tab walks out of the dialog. The comment claims i…

🪰 Gadfly · advisory

🟡 **Focus trap falls through (Tab escapes) when activeElement is outside {first, last, card} — external/stolen focus isn't pulled back in** _correctness, error-handling · flagged by 2 models_ - `web/src/components/ui/Modal.tsx:61-68` — the Tab-wrap logic only fires when `active === first` (Shift), `active === card` (Shift), or `active === last` (non-Shift). If `document.activeElement` is none of those — e.g. focus escaped to `<body>` or an element behind the backdrop because something stole focus after mount, or focus landed on a `[tabindex="-1"]` child that isn't the card — neither branch executes, `preventDefault` is not called, and Tab walks out of the dialog. The comment claims i… <sub>🪰 Gadfly · advisory</sub>
// escape. This is the robust case that covers focus having fallen to
// <body> — a control that was removed (ShareGardenModal's remove-share
// button) or disabled while busy — as well as any externally-stolen focus.
if (!card || !card.contains(active)) {
e.preventDefault()
;(e.shiftKey ? last : first).focus()
return
}
if (e.shiftKey && (active === first || active === card)) {
e.preventDefault()
last.focus()
1
@@ -70,7 +78,12 @@ export function Modal({
document.addEventListener('keydown', onKey)
return () => {
document.removeEventListener('keydown', onKey)
opener?.focus?.()
// Restore focus to the opener only if it's still in the document — the
// delete/clear flows this trap targets often remove the element that
// opened the dialog (a garden card, a plop row). A disconnected node's
// focus() silently no-ops and leaves focus on <body>, so fall through to
// that case explicitly rather than pretend it worked.
if (opener && opener.isConnected) opener.focus()
}
}, [])
+12 -6
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@@ -1,6 +1,6 @@
import { memo, type KeyboardEvent, type PointerEvent } from 'react'
import { objectTransform } from './shared'
import { objectDisplayName } from './kinds'
import { kindDef, objectDisplayName } from './kinds'
import type { EditorObject } from './types'
const DEFAULT_FILL = '#8a8a8a'
@@ -73,10 +73,13 @@ export const ObjectShape = memo(function ObjectShape({
const stroke = selected ? '#2f7a3e' : '#00000033'
const strokeWidth = selected ? 2 : 1
// A concise accessible name: the object's label plus its kind, e.g.
// "North Bed, raised bed". The dimensions aren't included — they need the
// garden's unit context this component doesn't hold — so they're a follow-up.
const label = `${objectDisplayName(object)}, ${object.kind.replace(/_/g, ' ')}`
// A concise accessible name: the object's label plus its kind's canonical
// label, e.g. "North Bed, In-ground" — reusing kindDef so it never diverges
// from what the UI shows (an ad-hoc kind.replace() gave "in ground"). The
// dimensions aren't included; they need the garden's unit context this
Outdated
Review

🟠 Ad-hoc kind string formatting duplicates existing kindDef labels

correctness, maintainability · flagged by 4 models

  • web/src/editor/ObjectShape.tsx:79 — The accessible label builds the kind display string with object.kind.replace(/_/g, ' '), duplicating a concern that kindDef() in ./kinds.ts already solves. kindDef returns curated, Title Case labels (e.g. "Grow bag", "In-ground") while the regex produces lowercase, unhyphenated output ("grow bag", "in ground"). This creates an inconsistency with the rest of the UI (e.g. JournalPanel uses objectDisplayName, which respects kindDef l…

🪰 Gadfly · advisory

🟠 **Ad-hoc kind string formatting duplicates existing kindDef labels** _correctness, maintainability · flagged by 4 models_ - **`web/src/editor/ObjectShape.tsx:79`** — The accessible label builds the kind display string with `object.kind.replace(/_/g, ' ')`, duplicating a concern that `kindDef()` in `./kinds.ts` already solves. `kindDef` returns curated, Title Case labels (e.g. `"Grow bag"`, `"In-ground"`) while the regex produces lowercase, unhyphenated output (`"grow bag"`, `"in ground"`). This creates an inconsistency with the rest of the UI (e.g. `JournalPanel` uses `objectDisplayName`, which respects `kindDef` l… <sub>🪰 Gadfly · advisory</sub>
// component doesn't hold, so they're a follow-up.
const kindLabel = kindDef(object.kind)?.label ?? object.kind
const label = `${objectDisplayName(object)}, ${kindLabel}`
// Keyboard focus needs to be VISIBLE — that's the point of making the canvas
// keyboard-reachable. The `object-shape` class carries a :focus-visible rule
@@ -93,7 +96,10 @@ export const ObjectShape = memo(function ObjectShape({
role="button"
Review

🟠 aria-pressed misused on non-toggle role="button"; object selection is not a toggle action

correctness · flagged by 2 models

  • web/src/editor/ObjectShape.tsx:96aria-pressed={selected} on role="button" advertises a toggle button to screen readers (pressed / not pressed). The keyboard action (handleKey) always calls onSelect(object.id); there is no path that deselects the object when Enter/Space is pressed again on an already-selected item, so the toggle semantics are misleading. A screen reader user will expect the state to flip on second activation, which it does not. Fix: remove aria-pressed. I…

🪰 Gadfly · advisory

🟠 **aria-pressed misused on non-toggle role="button"; object selection is not a toggle action** _correctness · flagged by 2 models_ - **`web/src/editor/ObjectShape.tsx:96`** — `aria-pressed={selected}` on `role="button"` advertises a toggle button to screen readers (pressed / not pressed). The keyboard action (`handleKey`) always calls `onSelect(object.id)`; there is no path that deselects the object when Enter/Space is pressed again on an already-selected item, so the toggle semantics are misleading. A screen reader user will expect the state to flip on second activation, which it does not. **Fix:** remove `aria-pressed`. I… <sub>🪰 Gadfly · advisory</sub>
tabIndex={0}
aria-label={label}
aria-pressed={selected}
// aria-current, not aria-pressed: selecting an object isn't a toggle (a
// toggle is what aria-pressed means). aria-current marks it as the active
// item among the objects. Omitted, not "false", when unselected.
aria-current={selected || undefined}
style={{ cursor: 'pointer' }}
>
{object.shape === 'circle' ? (