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AlertDialog — spec

Synthesized from shadcn-ui alert-dialog (Radix). Modal confirmation dialog for actions that require explicit user acknowledgment. Distinct from Modal (general-purpose) and Toast (transient).

When to use

  • Destructive actions that can't be undone: "Delete account?", "Discard unsaved changes?"
  • Significant state changes: "Cancel subscription?", "Sign out everywhere?"
  • Critical confirmations in payment / financial flows.

When NOT to use: - Routine confirmations (use Toast with undo instead). - Form submissions (let the form's submit button speak for itself). - Loading / progress (use Modal or Toast).

AlertDialog vs Modal vs Toast

AlertDialog Modal Toast
Cancellable via Esc / outside-click Yes for cancel; no destructive default Yes n/a
Default focus Cancel button First focusable n/a
Use Destructive confirmation Forms, settings, content Transient feedback
Backdrop click Closes (= cancel) Closes (= dismiss) n/a

The key behavioral difference: AlertDialog defaults focus to Cancel so accidental Enter doesn't fire a destructive action.

Anatomy

┌──────────────────────────────────┐
│                                  │
│  ⚠  Delete this project?          │   ← title with icon
│                                  │
│  This will permanently delete    │   ← description
│  the project and all its data.   │
│  This action cannot be undone.   │
│                                  │
│       [Cancel] [Delete]          │   ← Cancel default focus
│        ↑                         │
│   default focus                  │
└──────────────────────────────────┘

API

<AlertDialog>
  <AlertDialog.Trigger asChild>
    <Button variant="destructive">Delete project</Button>
  </AlertDialog.Trigger>
  <AlertDialog.Content>
    <AlertDialog.Header>
      <AlertDialog.Title>Delete this project?</AlertDialog.Title>
      <AlertDialog.Description>
        This will permanently delete the project and all its data.
        This action cannot be undone.
      </AlertDialog.Description>
    </AlertDialog.Header>
    <AlertDialog.Footer>
      <AlertDialog.Cancel>Cancel</AlertDialog.Cancel>
      <AlertDialog.Action onClick={handleDelete}>
        Delete
      </AlertDialog.Action>
    </AlertDialog.Footer>
  </AlertDialog.Content>
</AlertDialog>

Composition

Part Purpose
Trigger Element that opens the dialog
Content The modal panel
Header Title + description region
Title Heading; identifies the question
Description Explanation of consequences
Footer Action row
Cancel Safe / dismissive action (default focus)
Action Confirming / destructive action

States

State Visual
Closed Hidden
Opening Backdrop fade + content scale (200ms)
Open Visible, focus on Cancel, body scroll locked
Action loading Action button shows spinner; both buttons disabled
Closing Reverse

Tokens consumed

--color-bg-overlay-scrim           (backdrop)
--color-bg-default                 (dialog bg)
--color-fg-default
--color-error-default              (destructive variant title icon + Action)
--color-warning-default            (warning variant)
--shadow-overlay
--radius-lg
--space-md, --space-lg
--motion-medium
--ease-out
--z-overlay

Accessibility

  • Content: role="alertdialog" (NOT dialog) — interrupts screen readers.
  • aria-labelledby references Title.
  • aria-describedby references Description.
  • Focus trap on open; focus defaults to Cancel (the safe option).
  • Esc triggers Cancel (not Action).
  • Backdrop click triggers Cancel.
  • Enter on focused button activates that button (default = Cancel = safe).
  • Touch target ≥ 44pt for both buttons.

Korean conventions

삭제하시겠습니까?

이 프로젝트와 관련된 모든 데이터가 영구적으로 삭제되며,
복구할 수 없습니다.

[취소]  [삭제]
  • 합쇼체 typical for destructive confirmations ("...하시겠습니까?")
  • 해요체 OK for casual brand voice ("...할까요?")
  • "취소" for Cancel; "삭제" / "확인" / "동의" for Action
  • Avoid "OK" / "예" alone — use a verb that names the action

Code example

function DeleteProjectButton({ project }: Props) {
  const [loading, setLoading] = useState(false);

  const handleDelete = async () => {
    setLoading(true);
    try {
      await api.deleteProject(project.id);
      toast.success("프로젝트가 삭제되었습니다");
    } finally {
      setLoading(false);
    }
  };

  return (
    <AlertDialog>
      <AlertDialog.Trigger asChild>
        <Button variant="destructive">
          <TrashIcon /> 프로젝트 삭제
        </Button>
      </AlertDialog.Trigger>
      <AlertDialog.Content>
        <AlertDialog.Header>
          <AlertDialog.Title>이 프로젝트를 삭제하시겠습니까?</AlertDialog.Title>
          <AlertDialog.Description>
            <strong>{project.name}</strong> 및 관련된 모든 데이터가
            영구적으로 삭제되며, 복구할 수 없습니다.
          </AlertDialog.Description>
        </AlertDialog.Header>
        <AlertDialog.Footer>
          <AlertDialog.Cancel disabled={loading}>취소</AlertDialog.Cancel>
          <AlertDialog.Action
            onClick={handleDelete}
            disabled={loading}
            className="bg-destructive"
          >
            {loading ? "삭제 중..." : "삭제"}
          </AlertDialog.Action>
        </AlertDialog.Footer>
      </AlertDialog.Content>
    </AlertDialog>
  );
}

Edge cases

  • Async action with error: keep dialog open after error; show inline error message; let user retry or cancel.
  • Action requires more context: pre-fill Description with consequence detail (file count, last edit date, undoable for X days).
  • Multi-step destructive flow: chain AlertDialogs OR convert to a wizard with summary at end.
  • Type-to-confirm pattern (delete repo on GitHub): replace simple Cancel/Action with a text input requiring exact name match.
  • Stacking: avoid AlertDialog inside AlertDialog. Sequence them or rethink flow.
  • RTL: button order reverses (Action left, Cancel right) per RTL convention.
  • Reduced motion: skip scale animation; instant.

Don't

  • Don't use AlertDialog for routine confirmations — use Toast with Undo for delete-with-undo flows.
  • Don't make Action the default-focused button. Cancel is safer.
  • Don't omit the Description for destructive actions. Users need consequence info.
  • Don't use vague labels like "OK / Cancel". Name the action ("Delete project").
  • Don't auto-close after Action without showing success feedback (Toast / inline).
  • Don't disable Esc — accessibility requires it.

References

Cross-reference