# FormField

> Fieldset/legend wrapper for a group of controls (radio sets, checkbox clusters, composite fields), with a group description and a group-level error. Individual controls own their own label, error and helper text.

- Status: stable
- Group: form
- Page: https://www.digitaltableteur.com/design-system/components/form-field
- Contract: https://www.digitaltableteur.com/contracts/v1/FormField.contract.json

## When to use

FormField names a group of controls with a fieldset legend: radio sets, checkbox clusters, composite fields like a date range. Individual controls own their own label, error and helperText (the field-wrapper convention), so FormField exists only for the group case, adding a legend, an optional description and a group-level error.

## When not to use

- Do not render a bare `<label>` + `<input>` next to a `FormField` in the same form; the visual rhythm desyncs.
- Do not wrap a single labeled control; TextInput, Select, Checkbox and friends carry their own label/error/helperText.
- Do not use it as a layout box; it renders a real fieldset with announcement semantics.
- Do not use it as a layout box; it renders a real fieldset and its legend is announced on every control inside.

## Look-alikes

- GroupLabel: Do not name a radio or checkbox set with as="label"; a label names one control. Use as="legend" inside a fieldset, or FormField.
- Label: Do not use Label as a heading above multiple controls; use FormField's group mode or a fieldset legend.

## Props

| Prop | Type | Default | Description | Required |
| --- | --- | --- | --- | --- |
| `legend` | `string` | none | Accessible name for the group of controls, rendered as a `<fieldset>` `<legend>`. | Yes |
| `children` | `ReactNode` | none | The grouped controls; each keeps its own label. | Yes |
| `groupDescription` | `string` | none | Helper text shown under the legend and referenced from the fieldset `aria-describedby`. | No |
| `error` | `string` | none | Group-level error message shown after the controls as an alert and referenced from the fieldset `aria-describedby`. | No |
| `required` | `boolean` | none | Appends a visual asterisk to the legend. | No |
| `disabled` | `boolean` | none | Disables every contained control via the fieldset. | No |
| `hideLegend` | `boolean` | `false` | Keeps the legend as the group's accessible name but hides it visually, for a group whose visible heading already names it. | No |
| `className` | `string` | none | Merged onto the fieldset. | No |

## Variants

No variant dimensions and no props with a fixed set of values.

## Invalid combinations

The contract records no invalid combinations.

## Keyboard

| Key | Behaviour |
| --- | --- |
| General | FormField is not focusable and adds no keyboard behaviour; Tab moves through the contained controls. |

## Rules

Every item under When not to use is a MUST NOT. MUST and SHOULD follow RFC 2119.

| Level | Rule | How it is checked |
| --- | --- | --- |
| MUST | ARIA: Renders a native `<fieldset>` whose `<legend>` (GroupLabel) is the group's accessible name; `disabled` is applied through the fieldset. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: When `error` is set, it renders after the controls in a `<p role='alert'>`. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: The fieldset `aria-describedby` references `groupDescription` and then `error` (each with a generated id), so the group description and group error are announced as the group's description; with neither set, no `aria-describedby` is rendered. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: When `required`, the legend asterisk is aria-hidden; each control owns its own `aria-required`. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | Required stories produce no axe violations at the configured severity. | Automated by `npm run test:stories:matrix:ci`. WCAG 2.5.8. |
| MUST | The accessibility tree (role, name, state) matches the committed snapshot for every required story. | Automated by `npm run test:stories:matrix:ci`. WCAG 1.3.1, 4.1.2. |
| MUST | The component remains legible and operable under a real browser forced-colors: active pass. | Automated by `npm run test:stories:hc`. |
| MUST | Every documented keyboard interaction works as specified. | Not yet verified: no evidence record. WCAG 2.1.1, 2.1.2. |
| MUST | A human completed an end-to-end accessibility review of this component. | Manual review, last on 2026-11-04. |
| SHOULD | Use it whenever two or more controls answer one question (Notification channels, Opening hours). | Not stated in the contract. |
| SHOULD | Write the legend as the question or category; each control's own label then reads as an answer. | Not stated in the contract. |
| SHOULD | Use groupDescription for guidance that applies to the whole set, like Pick at least one. | Not stated in the contract. |
| SHOULD | Put cross-control validation in the group error prop; per-control failures belong on the control's own error. | Not stated in the contract. |
| SHOULD NOT | Do not wrap a single labeled control; TextInput, Select, Checkbox and friends carry their own label, error and helper text. | Not stated in the contract. |

## Install and import

- Install: `npm install @digitaltableteur/react` (version 0.9.1, restricted access on npm).
- Import: `import { FormField } from "@digitaltableteur/react";`
- Entry point: `@digitaltableteur/react/forms` exports it too.
- Styles: import `@digitaltableteur/react/style.css` once at the app boundary.
- Also available as the custom element `<dt-form-field>`; see the custom elements manifest.

## Links

- Machine-readable contract (Design System Contract 1.0): https://www.digitaltableteur.com/contracts/v1/FormField.contract.json
- Markdown version of this page: https://www.digitaltableteur.com/design-system/components/form-field.md
- Component index as JSON: https://www.digitaltableteur.com/design-system/components.json
- All components: https://www.digitaltableteur.com/design-system/components
- Source: The implementation lives in a private repository. This page, its Markdown twin and the contract are generated from it at build time and are the public source of truth.