# Checkbox

Mithilfe einer Checkbox kann ein User eine Option auswählen oder abwählen. Bei der Verwendung mehrerer Checkboxen wird im Normalfall die CheckboxGroup verwendet.

## Overview

# Playground

Verwende `<Checkbox />` zusammen mit einer eingebetteten Beschriftung, um eine
darzustellen.

```tsx
import { Checkbox } from "@mittwald/flow-react-components";

<Checkbox>
  Ich stimme den AGBs zu und bestätige, dass ich die
  Datenschutzhinweise zur Kenntnis genommen habe.
</Checkbox>
```

---

# Indeterminated

Die Property `isIndeterminate` zeigt an, dass sich eine Checkbox in einem
visuell uneindeutigen Zustand befindet – also weder vollständig ausgewählt noch
vollständig abgewählt ist. Sie wird verwendet, um übergeordnete Checkboxen
darzustellen, bei denen nur ein Teil der untergeordneten Optionen ausgewählt
wurde.

```tsx
import { Checkbox } from "@mittwald/flow-react-components";

<Checkbox isIndeterminate>
  Ich stimme den AGBs zu und bestätige, dass ich die
  Datenschutzhinweise zur Kenntnis genommen habe.
</Checkbox>
```

---

# Disabled

In bestimmten Fällen kann eine Checkbox den State **Disabled** haben. In diesem
Fall ist die Auswahloption für den User deaktiviert und kann nicht ausgewählt
werden.

```tsx
import { Checkbox } from "@mittwald/flow-react-components";

<Checkbox isDisabled>
  Ich stimme den AGBs zu und bestätige, dass ich die
  Datenschutzhinweise zur Kenntnis genommen habe.
</Checkbox>
```

---

# Kombiniere mit ...

## React Hook Form

```tsx
import {
  Checkbox,
  Section,
} from "@mittwald/flow-react-components";
import { useForm } from "react-hook-form";
import {
  Form,
  SubmitButton,
  typedField,
} from "@mittwald/flow-react-components/react-hook-form";
import { sleep } from "@/content/04-components/actions/action/examples/lib";

export default () => {
  const form = useForm<{ acceptTerms: boolean }>();
  const Field = typedField(form);

  return (
    <Section>
      <Form form={form} onSubmit={sleep}>
        <Field
          name="acceptTerms"
          rules={{ required: true }}
        >
          <Checkbox>
            Ich stimme den AGBs zu und bestätige, dass ich
            die Datenschutzhinweise zur Kenntnis genommen
            habe.
          </Checkbox>
        </Field>
        <SubmitButton>Speichern</SubmitButton>
      </Form>
    </Section>
  );
}
```


## Develop

# Properties

| Property | Type | Default | Description |
| --- | --- | --- | --- |
| `inputClassName` | `string` | - | - |
| `id` | `string` | - | The element's unique identifier. See [MDN](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/id). |
| `translate` | `"yes" \| "no"` | - | - |
| `className` | `ClassNameOrFunction<CheckboxGroupRenderProps>` | `'react-aria-CheckboxGroup'` | The CSS [className](https://developer.mozilla.org/en-US/docs/Web/API/Element/className) for the element. A function may be provided to compute the class based on component state. |
| `style` | `StyleOrFunction<TooltipRenderProps>` | - | The inline [style](https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/style) for the element. A function may be provided to compute the style based on component state. |
| `render` | `DOMRenderFunction<"div", TooltipRenderProps>` | - | Overrides the default DOM element with a custom render function. This allows rendering existing components with built-in styles and behaviors such as router links, animation libraries, and pre-styled components. Requirements: - You must render the expected element type (e.g. if `<button>` is expected, you cannot render an `<a>`). - Only a single root DOM element can be rendered (no fragments). - You must pass through props and ref to the underlying DOM element, merging with your own prop as appropriate. |
| `dir` | `string` | - | - |
| `lang` | `string` | - | - |
| `hidden` | `boolean` | - | - |
| `inert` | `boolean` | - | - |
| `validationBehavior` | `"native" \| "aria"` | `'native'` | Whether to use native HTML form validation to prevent form submission when the value is missing or invalid, or mark the field as required or invalid via ARIA. |
| `isDisabled` | `boolean` | - | Whether the input is disabled. |
| `isReadOnly` | `boolean` | - | Whether the input can be selected but not changed by the user. |
| `isRequired` | `boolean` | - | Whether user input is required on the input before form submission. |
| `isInvalid` | `boolean` | - | Whether the input value is invalid. |
| `validate` | `((value: TimeValue) => true \| ValidationError)` | - | A function that returns an error message if a given value is invalid. Validation errors are displayed to the user when the form is submitted if `validationBehavior="native"`. For realtime validation, use the `isInvalid` prop instead. |
| `autoFocus` | `boolean` | - | Whether the element should receive focus on render. |
| `value` | `string` | - | The value of the input element, used when submitting an HTML form. See [MDN](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input#htmlattrdefvalue). |
| `name` | `string` | - | The name of the input element, used when submitting an HTML form. See [MDN](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input#htmlattrdefname). |
| `form` | `string` | - | The `<form>` element to associate the input with. The value of this attribute must be the id of a `<form>` in the same document. See [MDN](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/input#form). |
| `slot` | `string` | - | A slot name for the component. Slots allow the component to receive props from a parent component. An explicit `null` value indicates that the local props completely override all props received from a parent. |
| `excludeFromTabOrder` | `boolean` | - | Whether to exclude the element from the sequential tab order. If true, the element will not be focusable via the keyboard by tabbing. This should be avoided except in rare scenarios where an alternative means of accessing the element or its functionality via the keyboard is available. |
| `defaultSelected` | `boolean` | - | Whether the element should be selected (uncontrolled). |
| `isSelected` | `boolean` | - | Whether the element should be selected (controlled). |
| `isIndeterminate` | `boolean` | - | Indeterminism is presentational only. The indeterminate visual representation remains regardless of user interaction. |
| `children` | `ReactNode` | - | - |
| `wrapWith` | `ReactElement<unknown, string \| JSXElementConstructor<any>>` | - | - |
| `ref` | `Ref<HTMLSpanElement>` | - | Allows getting a ref to the component instance. Once the component unmounts, React will set `ref.current` to `null` (or call the ref with `null` if you passed a callback ref). @see [React Docs](https://react.dev/learn/referencing-values-with-refs#refs-and-the-dom) |
| `key` | `Key` | - | - |

### Events

| Property | Type | Default | Description |
| --- | --- | --- | --- |
| `onClick` | `((e: MouseEvent<FocusableElement, MouseEvent>) => void)` | - | **Not recommended – use `onPress` instead.** `onClick` is an alias for `onPress` provided for compatibility with other libraries. `onPress` provides additional event details for non-mouse interactions. |
| `onClickCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onAuxClick` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onAuxClickCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onContextMenu` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onContextMenuCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onDoubleClick` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onDoubleClickCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseDown` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseDownCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseEnter` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseLeave` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseMove` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseMoveCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseOut` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseOutCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseOver` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseOverCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseUp` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onMouseUpCapture` | `MouseEventHandler<HTMLDivElement>` | - | - |
| `onTouchCancel` | `TouchEventHandler<HTMLDivElement>` | - | - |
| `onTouchCancelCapture` | `TouchEventHandler<HTMLDivElement>` | - | - |
| `onTouchEnd` | `TouchEventHandler<HTMLDivElement>` | - | - |
| `onTouchEndCapture` | `TouchEventHandler<HTMLDivElement>` | - | - |
| `onTouchMove` | `TouchEventHandler<HTMLDivElement>` | - | - |
| `onTouchMoveCapture` | `TouchEventHandler<HTMLDivElement>` | - | - |
| `onTouchStart` | `TouchEventHandler<HTMLDivElement>` | - | - |
| `onTouchStartCapture` | `TouchEventHandler<HTMLDivElement>` | - | - |
| `onPointerDown` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerDownCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerMove` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerMoveCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerUp` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerUpCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerCancel` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerCancelCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerEnter` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerLeave` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerOver` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerOverCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerOut` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onPointerOutCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onGotPointerCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onGotPointerCaptureCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onLostPointerCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onLostPointerCaptureCapture` | `PointerEventHandler<HTMLDivElement>` | - | - |
| `onScroll` | `UIEventHandler<HTMLDivElement>` | - | - |
| `onScrollCapture` | `UIEventHandler<HTMLDivElement>` | - | - |
| `onWheel` | `WheelEventHandler<HTMLDivElement>` | - | - |
| `onWheelCapture` | `WheelEventHandler<HTMLDivElement>` | - | - |
| `onAnimationStart` | `AnimationEventHandler<HTMLDivElement>` | - | - |
| `onAnimationStartCapture` | `AnimationEventHandler<HTMLDivElement>` | - | - |
| `onAnimationEnd` | `AnimationEventHandler<HTMLDivElement>` | - | - |
| `onAnimationEndCapture` | `AnimationEventHandler<HTMLDivElement>` | - | - |
| `onAnimationIteration` | `AnimationEventHandler<HTMLDivElement>` | - | - |
| `onAnimationIterationCapture` | `AnimationEventHandler<HTMLDivElement>` | - | - |
| `onTransitionCancel` | `TransitionEventHandler<HTMLDivElement>` | - | - |
| `onTransitionCancelCapture` | `TransitionEventHandler<HTMLDivElement>` | - | - |
| `onTransitionEnd` | `TransitionEventHandler<HTMLDivElement>` | - | - |
| `onTransitionEndCapture` | `TransitionEventHandler<HTMLDivElement>` | - | - |
| `onTransitionRun` | `TransitionEventHandler<HTMLDivElement>` | - | - |
| `onTransitionRunCapture` | `TransitionEventHandler<HTMLDivElement>` | - | - |
| `onTransitionStart` | `TransitionEventHandler<HTMLDivElement>` | - | - |
| `onTransitionStartCapture` | `TransitionEventHandler<HTMLDivElement>` | - | - |
| `onFocus` | `((e: FocusEvent<Element, Element>) => void)` | - | Handler that is called when the element receives focus. |
| `onBlur` | `((e: FocusEvent<Element, Element>) => void)` | - | Handler that is called when the element loses focus. |
| `onFocusChange` | `((isFocused: boolean) => void)` | - | Handler that is called when the element's focus status changes. |
| `onKeyDown` | `((e: KeyboardEvent) => void)` | - | Handler that is called when a key is pressed. |
| `onKeyUp` | `((e: KeyboardEvent) => void)` | - | Handler that is called when a key is released. |
| `onChange` | `((isSelected: boolean) => void)` | - | Handler that is called when the element's selection state changes. |
| `onPress` | `((e: PressEvent) => void)` | - | Handler that is called when the press is released over the target. |
| `onPressStart` | `((e: PressEvent) => void)` | - | Handler that is called when a press interaction starts. |
| `onPressEnd` | `((e: PressEvent) => void)` | - | Handler that is called when a press interaction ends, either over the target or when the pointer leaves the target. |
| `onPressChange` | `((isPressed: boolean) => void)` | - | Handler that is called when the press state changes. |
| `onPressUp` | `((e: PressEvent) => void)` | - | Handler that is called when a press is released over the target, regardless of whether it started on the target or not. |
| `onHoverStart` | `((e: HoverEvent) => void)` | - | Handler that is called when a hover interaction starts. |
| `onHoverEnd` | `((e: HoverEvent) => void)` | - | Handler that is called when a hover interaction ends. |
| `onHoverChange` | `((isHovering: boolean) => void)` | - | Handler that is called when the hover state changes. |

### Accessibility

| Property | Type | Default | Description |
| --- | --- | --- | --- |
| `aria-label` | `string` | - | Defines a string value that labels the current element. |
| `aria-labelledby` | `string` | - | Identifies the element (or elements) that labels the current element. |
| `aria-describedby` | `string` | - | Identifies the element (or elements) that describes the object. |
| `aria-details` | `string` | - | Identifies the element (or elements) that provide a detailed, extended description for the object. |
| `aria-controls` | `string` | - | Identifies the element (or elements) whose contents or presence are controlled by the current element. |
| `aria-errormessage` | `string` | - | Identifies the element that provides an error message for the object. |


## Guidelines

# Grundlagen

Eine Checkbox funktioniert in der Handhabung nahezu identisch wie ein
[CheckboxButton](/04-components/form-controls/checkbox-button/overview). Der
Unterschied liegt im Erscheinungsbild. Je nach Gestaltung der Benutzeroberfläche
oder je nach Anwendungsfall sollte individuell entschieden werden, welche der
beiden Components sinnvoller ist.

## Best practices

Achte bei der Verwendung einer Checkbox darauf, dass ...

- sie immer eine Beschriftung hat.
- die Beschriftung kurz und eindeutig ist. Sie sollte stets mit einem
  Großbuchstaben beginnen.
- die Beschriftung in der Regel ohne Punkt endet – es sei denn, sie ist ein
  vollständiger Satz.
- der initiale Zustand (ausgewählt/nicht ausgewählt) nachvollziehbar und
  sinnvoll gewählt ist.
- der Zwischenzustand „Indeterminate“ nur in Verbindung mit untergeordneten
  Checkboxen verwendet wird.
- das An- und Abhaken einer Checkbox keine anderen Checkboxen verändert – mit
  Ausnahme einer übergeordneten Checkbox.
- bei mehreren Checkboxen die Reihenfolge logisch und nachvollziehbar ist (siehe
  [CheckboxGroup](/04-components/form-controls/checkbox-group/overview)).

## Verwendung

Verwende eine Checkbox, um ...

- dem User die Auswahl einer oder mehrerer Optionen zu ermöglichen.
- einzelne Zustimmungen (z. B. AGBs) vom User einzuholen.

## Checkbox vs. Switch

Mit den Components Checkbox und
[Switch](/04-components/form-controls/switch/overview) können Optionen
aktiviert/ausgewählt werden. Um die Unterschiede klarer zu machen, hier einige
hilfreiche Anhaltspunkte.

  

- dem User eine Auswahloption zur Bestätigung zu geben.
    - Auswahlmöglichkeiten in einem Formular anzubieten, die gespeichert werden müssen.

  

- eine Funktion direkt zu aktivieren oder zu deaktivieren.
    - eine Einstellung sofort zu ändern, ohne sie separat speichern zu müssen.

