# Button
To implement Button component into your project you'll need to add the import:
```jsx
import Button from "@kiwicom/orbit-components/lib/Button";
```
After adding import into your project you can use it simply like:
```jsx
```
## Props
Table below contains all types of the props available in Button component.
| Name | Type | Default | Description |
| :----------- | :------------------------- | :---------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| ariaControls | `string` | | Id of the element the button controls. |
| ariaExpanded | `boolean` | | Tells screen reader the controlled element from `ariaControls` is expanded |
| asComponent | `string \| React.Element` | `"button"` | The component used for the root node. |
| fullWidth | `boolean` | `false` | If `true`, the Button will grow up to the full width of its container. |
| centered | `boolean` | `false` | Can only be used when `fullWidth` is true and if `iconLeft` and/or `iconRight` are defined. If `centered` prop is `true`, the Button will center everything. |
| circled | `boolean` | `false` | If `true`, the Button will have circular shape. |
| children | `React.Node` | | The content of the Button. [See Functional specs](#functional-specs) |
| dataTest | `string` | | Optional prop for testing purposes. |
| id | `string` | | Set `id` for `Button` |
| disabled | `boolean` | `false` | If `true`, the Button will be disabled. |
| download | `boolean \| string` | | Can only be used when `href` is defined. Adds the `download` attribute to the the anchor element. |
| external | `boolean` | `false` | If `true`, the Button opens link in a new tab. [See Functional specs](#functional-specs) |
| href | `string` | | The URL of the link to open when Button is clicked. [See Functional specs](#functional-specs) |
| iconLeft | `React.Node` | | The displayed icon on the left. |
| iconRight | `React.Node` | | The displayed icon on the right. |
| loading | `boolean` | `false` | If `true`, the loading glyph will be displayed. |
| onClick | `event => void \| Promise` | | Function for handling onClick event. |
| ref | `func` | | Prop for forwarded ref of the Button. |
| rel | `string` | | Specifies the rel of an element. [See Functional specs](#functional-specs) |
| role | `string` | | Specifies the role of an element. |
| **size** | [`enum`](#enum) | `"normal"` | The size of the Button. |
| spaceAfter | `enum` | | Additional `margin-bottom` after component. [See this docs](https://github.com/kiwicom/orbit/tree/master/packages/orbit-components/src/common/getSpacingToken) |
| submit | `boolean` | `false` | If `true`, the Button will have `type="submit"` attribute, otherwise `type="button"`. |
| tabIndex | `string \| number` | | Specifies the tab order of an element. |
| title | `string` | | Adds `aria-label`. |
| **type** | [`enum`](#enum) | `"primary"` | The type of Button. |
| width | `string` | | The width of the Button. Can be any string - `100px`, `20%`. |
### enum
| type | size |
| :----------------- | :--------- |
| `"primary"` | `"small"` |
| `"secondary"` | `"normal"` |
| `"critical"` | `"large"` |
| `"white"` | |
| `"primarySubtle"` | |
| `"criticalSubtle"` | |
| `"bundleBasic"` | |
| `"bundleMedium"` | |
| `"bundleTop"` | |
## Functional specs
- When the `external` is specified, `noopener` value will be automatically added to attribute `rel` for security reason. Read more about it [here](https://web.dev/external-anchors-use-rel-noopener/).
* By passing the `href` prop into Button, it will render into `a` element. If you pass `asComponent` prop it will override this logic.
- If you want to render **Icon only Button**, you just need to let `children` prop empty and set up any `icon` you want to use.
* If you want to use the `asComponent` prop then **YourComponent** should accept at least `className`. Otherwise it won't be rendered with proper styling, e.g.:
```jsx
const YourComponent = props =>
```
If you specify the children of **YourComponent** component, it will override the children prop of Button component, e.g.:
```jsx
const YourComponent = props =>
YourComponent
;
```
- By default, a full width Button renders with the children centered. However, if `iconLeft` and/or `iconRight` are defined, the content will align to the left by default. In such scenario, the `centered` prop can be used to center everything.
## Accessibility
A button is mainly used for indicating an action, submitting a data, opening a modal etc. If you want to use Button for navigation consider using a `` for that.
- Use `ariaControls` prop to add `aria-controls` attribute to establish the relationship between button and element which is controlled by it. `aria-controls` works only with a unique `id` of an element.
- Use `ariaExpands` prop to add `aria-expands` to indicate screenreaders, that element controlled by button through `ariaControls` is expanded or not.
- Use `disabled` prop to indicate users that button is inactive and they can't interact with it.
- Use `role` and `tabIndex` when you are rendering `Button` to non-actionable HTML element as `div` or `span`. However, this should be done only in edge-cases as it is anti-pattern behavior.
- Use `title` to add `aria-label` when you need to add extra informations to screen readers or there is no `children` presented to be used as label.