Feat(web-react): Introduce Toast component

- solve #DS-1113

.storybook/assets/stylesheets/index.scss

@@ -27,6 +27,7 @@
 @forward '../../../packages/web/src/scss/components/Tag';
 @forward '../../../packages/web/src/scss/components/TextArea';
 @forward '../../../packages/web/src/scss/components/TextField';
+@forward '../../../packages/web/src/scss/components/Toast';
 @forward '../../../packages/web/src/scss/components/Tooltip';
 
 @forward '../../../packages/web/src/scss/utilities';

packages/web-react/src/components/Toast/README.md

@@ -0,0 +1,275 @@
+# Toast
+
+This is the React implementation of the [Toast][web-toast] component.
+
+Toast displays a brief, temporary notification that appears at a prescribed location of an application window.
+
+Toast is a composition of a few subcomponents:
+
+- [Toast](#toast)
+  - [ToastBar](#toastbar)
+
+## Toast
+
+The Toast component is a container responsible for positioning the [ToastBar](#toastbar) component. It is capable of
+handling even multiple toast messages at once, stacking them in a [queue](#toast-queue).
+
+```jsx
+import { Toast } from '@lmc-eu/spirit-web-react/components';
+```
+
+```jsx
+<Toast>
+  <!-- ToastBar components go here -->
+</Toast>
+```
+
+### Accessibility
+
+The wrapping Toast container has the [`role="log"`][mdn-role-log] attribute set (which results in an implicit
+[`aria-live`][mdn-aria-live] value of `polite`). Assistive technologies then announce any **dynamic changes** inside the
+container as they happen. In order for this to work, the Toast component **must be present in the DOM** on the initial
+page load, even when empty.
+
+### Alignment
+
+The Toast component is positioned at the bottom of the screen by default. It is also fixed to the bottom of the screen,
+so it will always be visible, even when the user scrolls. Available alignment options are derived from the
+[AlignmentX and AlignmentY][dictionary-alignment] dictionaries and are as follows:
+
+- `top` `left`,
+- `top` `center`,
+- `top` `right`,
+- `bottom` `left`,
+- `bottom` `center` (default),
+- `bottom` `right`.
+
+Use the `alignmentX` and `alignmentY` options to change the alignment of the Toast component.
+
+ℹ️ The `center` vertical alignment is not supported, as it would not make sense for a toast notification to be in the
+middle of the screen.
+
+Example:
+
+```jsx
+<Toast alignmentX="right" alignmentY="top">
+  <!-- ToastBar components go here -->
+</Toast>
+```
+
+### Responsive Alignment
+
+Pass an object to props to set different values for different breakpoints. The values will be applied from mobile to
+desktop and if not set for a breakpoint, the value from the previous breakpoint will be used.
+
+Example:
+
+```jsx
+<Toast alignmentX="{{ mobile: 'center', tablet: 'right' }}" alignmentY="top">
+  <!-- ToastBar components go here -->
+</Toast>
+```
+
+### Mobile Screens
+
+Positioning becomes trickier on mobile screens due to the presence of notches, rounded corners, and the virtual
+keyboard. The Toast component tries to find the best position to be visible using the following detection mechanisms:
+
+1. On **devices with rounded displays and/or notches** (e.g. iPhone X and newer), the Toast component is pushed inwards
+   to avoid the rounded corners. The `viewport-fit="cover"` meta tag is required for this feature to work:
+
+   ```html
+   <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover" />
+   ```
+
+2. **Android Chrome only:** When the vertical alignment is set to `bottom` and the virtual keyboard is open, the Toast
+   component is pushed upwards to avoid being covered by the keyboard. This feature requires the following JavaScript
+   snippet and is currently supported only in Chrome 94 on Android and later.
+
+   ```js
+   // Enable CSS to detect the presence of virtual keyboard:
+   if ('virtualKeyboard' in navigator) {
+     navigator.virtualKeyboard.overlaysContent = true;
+   }
+   ```
+
+### Toast Queue
+
+When multiple ToastBar components are present, they stack up in a queue, separated by a gap. The ToastBar components are
+sorted from top to bottom for the `top` vertical alignment, and from bottom to top for the `bottom` vertical alignment.
+
+👉 Please note the _actual_ order in the DOM is followed when users tab over the interface, no matter the _visual_
+order of the toast queue.
+
+#### Toast Queue Limitations
+
+While the Toast queue becomes scrollable when it does not fit the screen, we recommend displaying only a few toasts at
+once for several reasons:
+
+⚠️ **We strongly discourage from displaying too many toasts at once as it may cause the page to be unusable,
+especially on mobile screens. As of now, there is no automatic stacking of the toast queue items. It is the
+responsibility of the developer to ensure that the Toast queue does not overflow the screen.**
+
+⚠️ Please note that scrolling is not available on iOS devices due to a limitation in the WebKit engine.
+
+👉 Please note that the initial scroll position is always at the **top** of the queue.
+
+### API
+
+| Name         | Type                                                        | Default  | Required | Description                             |
+| ------------ | ----------------------------------------------------------- | -------- | -------- | --------------------------------------- |
+| `alignmentX` | [[AlignmentX dictionary][dictionary-alignment] \| `object`] | `center` | ✕        | Horizontal alignment of the toast queue |
+| `alignmentY` | [`top` \| `bottom` \| `object`]                             | `bottom` | ✕        | Vertical alignment of the toast queue   |
+
+On top of the API options, the components accept [additional attributes][readme-additional-attributes].
+If you need more control over the styling of a component, you can use [style props][readme-style-props]
+and [escape hatches][readme-escape-hatches].
+
+## ToastBar
+
+The ToastBar component is the actual toast notification. It is a simple container with a message and a few optional
+elements.
+
+Minimum example:
+
+```jsx
+import { ToastBar } from '@lmc-eu/spirit-web-react/components';
+```
+
+```jsx
+<ToastBar id="my-toast">Message only</ToastBar>
+```
+
+### Optional Icon
+
+An icon can be displayed in the ToastBar component, depending on the color of the ToastBar:
+
+```jsx
+<ToastBar id="my-toast" color="success" hasIcon>
+  Message with icon
+</ToastBar>
+```
+
+Alternatively, a custom icon can be used:
+
+```jsx
+<ToastBar id="my-toast" iconName="download">
+  Message with custom icon
+</ToastBar>
+```
+
+#### Default Icons According to Color Variant
+
+| Color name    | Icon name     |
+| ------------- | ------------- |
+| `danger`      | `danger`      |
+| `informative` | `info`        |
+| `inverted`    | `info`        |
+| `success`     | `check-plain` |
+| `warning`     | `warning`     |
+
+### Action Link
+
+An action link can be added to the ToastBar component:
+
+```jsx
+<ToastBar id="my-toast">
+  Message with action
+  <Link href="#" color="inverted" isUnderlined>
+    Action
+  </Link>
+</ToastBar>
+```
+
+👉 For the sake of flexibility, developers can pass the link as part of the message. However, it is strongly recommended
+to use the **inverted underlined** variant of the link (for all ToastBar colors) to make it stand out from the message.
+
+👉 **Do not put any important actions** like "Undo" in the ToastBar component (unless there are other means to perform
+said action), as it is very hard (if not impossible) to reach for users with assistive technologies. Read more about
+[Toast accessibility][scott-o-hara-toast] at Scott O'Hara's blog.
+
+### Colors
+
+The ToastBar component is available in all [emotion colors][dictionary-color], plus the `inverted` variant (default).
+Use the `color` option to change the color of the ToastBar component.
+
+For example:
+
+```jsx
+<ToastBar id="my-toast" color="success">
+  Success message
+</ToastBar>
+```
+
+### Opening the ToastBar
+
+Set `isOpen` prop to `true` to open a Toast **that is present in the DOM,** e.g.:
+
+```jsx
+<ToastBar id="my-toast" isOpen>
+  Opened ToastBar
+</ToastBar>
+```
+
+👉 Advanced toast queue control is not yet implemented.
+
+### Dismissible ToastBar
+
+To make the ToastBar dismissible, add the `isDismissible` prop along with a `onClose` function:
+
+```jsx
+<ToastBar id="my-toast" onClose={() => {}} isDismissible>
+  Dismissible message
+</ToastBar>
+```
+
+### API
+
+| Name            | Type                                                         | Default    | Required | Description                                                          |
+| --------------- | ------------------------------------------------------------ | ---------- | -------- | -------------------------------------------------------------------- |
+| `closeLabel`    | `string`                                                     | `Close`    | ✕        | Close label                                                          |
+| `color`         | [[Emotion Color dictionary][dictionary-color] \| `inverted`] | `inverted` | ✕        | Color variant                                                        |
+| `hasIcon`       | `bool`                                                       | `false` \* | ✕        | If true, an icon is shown along the message                          |
+| `iconName`      | `string`                                                     | `info` \*  | ✕        | Name of a custom icon to be shown along the message                  |
+| `id`            | `string`                                                     | —          | ✔        | Optional ToastBar ID. Required when `isDismissible` is set to `true` |
+| `isDismissible` | `bool`                                                       | `false`    | ✕        | If true, ToastBar can be dismissed by user                           |
+| `isOpen`        | `bool`                                                       | `true`     | ✕        | If true, ToastBar is visible                                         |
+| `onClose`       | `function`                                                   | —          | ✕        | Close button callback                                                |
+
+(\*) For each emotion color, a default icon is defined.
+The icons come from the [Icon package][icon-package], or from your custom source of icons.
+Read the section [Default Icons according to Color Variant](#default-icons-according-to-color-variant).
+
+On top of the API options, the components accept [additional attributes][readme-additional-attributes].
+If you need more control over the styling of a component, you can use [style props][readme-style-props]
+and [escape hatches][readme-escape-hatches].
+
+## Full Example
+
+```jsx
+import { Button, Toast, ToastBar } from '@lmc-eu/spirit-web-react/components';
+
+const [isOpen, setIsOpen] = React.useState(false)
+
+<Button onClick={() => setIsOpen(true)} aria-expanded={isOpen} aria-controls="my-toast">
+  {buttonLabel}
+</Button>
+
+<Toast>
+  <ToastBar id="my-toast" isOpen={isOpen} onClose={() => setIsOpen(false)} isDismissible>
+    Toast message
+    <Link href="#" color="inverted" isUnderlined>Action</Link>
+  </ToastBar>
+</Toast>
+```
+
+[web-toast]: https://github.com/lmc-eu/spirit-design-system/tree/main/packages/web/src/scss/components/Toast
+[mdn-role-log]: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/log_role
+[mdn-aria-live]: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-live
+[dictionary-alignment]: https://github.com/lmc-eu/spirit-design-system/blob/main/docs/DICTIONARIES.md#alignment
+[dictionary-color]: https://github.com/lmc-eu/spirit-design-system/blob/main/docs/DICTIONARIES.md#color
+[readme-additional-attributes]: https://github.com/lmc-eu/spirit-design-system/blob/main/packages/web-twig/README.md#additional-attributes
+[readme-escape-hatches]: https://github.com/lmc-eu/spirit-design-system/blob/main/packages/web-twig/README.md#escape-hatches
+[readme-style-props]: https://github.com/lmc-eu/spirit-design-system/blob/main/packages/web-twig/README.md#style-props
+[scott-o-hara-toast]: https://www.scottohara.me/blog/2019/07/08/a-toast-to-a11y-toasts.html
+[icon-package]: https://github.com/lmc-eu/spirit-design-system/tree/main/packages/icons

packages/web-react/src/components/Toast/Toast.tsx

@@ -0,0 +1,19 @@
+import classNames from 'classnames';
+import React from 'react';
+import { useStyleProps } from '../../hooks';
+import { SpiritToastProps } from '../../types';
+import { useToastStyleProps } from './useToastStyleProps';
+
+const Toast = (props: SpiritToastProps) => {
+  const { children, alignmentX = 'center', alignmentY = 'bottom', ...restProps } = props;
+  const { classProps, props: modifiedProps } = useToastStyleProps({ ...restProps, alignmentX, alignmentY });
+  const { styleProps, props: otherProps } = useStyleProps(modifiedProps);
+
+  return (
+    <div {...otherProps} {...styleProps} className={classNames(classProps.root, styleProps.className)} role="log">
+      <div className={classProps.queue}>{children}</div>
+    </div>
+  );
+};
+
+export default Toast;

packages/web-react/src/components/Toast/ToastBar.tsx

@@ -0,0 +1,76 @@
+import classNames from 'classnames';
+import React, { MutableRefObject, useRef } from 'react';
+import { Transition, TransitionStatus } from 'react-transition-group';
+import { useStyleProps } from '../../hooks';
+import { SpiritToastBarProps } from '../../types';
+import { Button } from '../Button';
+import { Icon } from '../Icon';
+import { VisuallyHidden } from '../VisuallyHidden';
+import {
+  DEFAULT_TOAST_COLOR,
+  ICON_BOX_SIZE,
+  TOAST_BAR_CLOSE_BUTTON_LABEL_DEFAULT,
+  TRANSITIONING_STYLES,
+  TRANSITION_DURATION,
+} from './constants';
+import { useToastBarStyleProps } from './useToastBarStyleProps';
+import { useToastIcon } from './useToastIcon';
+
+const ToastBar = (props: SpiritToastBarProps) => {
+  const {
+    id,
+    children,
+    closeLabel = TOAST_BAR_CLOSE_BUTTON_LABEL_DEFAULT,
+    color = DEFAULT_TOAST_COLOR,
+    hasIcon,
+    iconName,
+    isDismissible,
+    isOpen = true,
+    onClose = () => {},
+    ...restProps
+  } = props;
+  const rootElementRef: MutableRefObject<HTMLDivElement | null> = useRef(null);
+  const toastIconName = useToastIcon({ color, iconName });
+  const { classProps, props: modifiedProps } = useToastBarStyleProps({
+    ...restProps,
+    color,
+    isDismissible,
+    id,
+  });
+  const { styleProps, props: otherProps } = useStyleProps(modifiedProps);
+
+  return (
+    <Transition in={isOpen} nodeRef={rootElementRef} timeout={TRANSITION_DURATION} unmountOnExit>
+      {(transitionState: TransitionStatus) => (
+        <div
+          {...styleProps}
+          {...otherProps}
+          className={classNames(classProps.root, TRANSITIONING_STYLES[transitionState], styleProps.className)}
+          ref={rootElementRef}
+        >
+          <div className={classProps.content}>
+            {(hasIcon || iconName) && <Icon name={toastIconName} boxSize={ICON_BOX_SIZE} />}
+            <div className={classProps.message}>{children}</div>
+          </div>
+
+          {isDismissible && onClose && (
+            <Button
+              type="button"
+              color={color}
+              onClick={onClose}
+              size="small"
+              isSquare
+              aria-expanded={isOpen}
+              aria-controls={id}
+            >
+              <Icon name="close" />
+              <VisuallyHidden>{closeLabel}</VisuallyHidden>
+            </Button>
+          )}
+        </div>
+      )}
+    </Transition>
+  );
+};
+
+export default ToastBar;