[BD-8468][BpkCarousel] new component for mobile

examples/bpk-component-carousel/example.js

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+import BpkCarousel from '../../packages/bpk-component-carousel'
+
+const DemoImages = () => (
+    <img src="https://d2xf5gjipzd8cd.cloudfront.net/available/949043373/949043373_343x132.jpg" alt='' />
+)
+
+const imagesList = [<DemoImages />,<img src='https://d2xf5gjipzd8cd.cloudfront.net/available/758391025/758391025_343x132.jpg' alt='' />, <DemoImages />, <DemoImages />, <DemoImages />, <DemoImages />]
+
+
+const DefaultExample = () => (
+  <BpkCarousel images={imagesList} initialImageIndex={1}/>
+);
+
+export default DefaultExample

examples/bpk-component-carousel/stories.js

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+import BpkCarousel from '../../packages/bpk-component-carousel'
+
+import DefaultExample from './example'
+
+export default {
+  title: 'bpk-component-carousel',
+  component: BpkCarousel,
+};
+
+
+export const Default = DefaultExample;

packages/bpk-component-carousel/README.md

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+# bpk-component-boilerplate
+
+> Backpack carousel component.
+
+## Installation
+
+Check the main [Readme](https://github.com/skyscanner/backpack#usage) for a complete installation guide.
+
+## Usage
+
+```tsx
+import BpkBoilerplate from '@skyscanner/backpack-web/bpk-component-carousel';
+
+const imageChangeHandler = () => {
+  console.log('Image Changed')
+}
+
+export default () => (
+  <BpkCarousel
+    images={[ <img src="https://url/1_WxH.jpg" alt='image' />]}
+    initialImageIndex={2}
+    onImageChanged={imageChangeHandler}
+  />
+  );
+```

packages/bpk-component-carousel/index.ts

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+/*
+ * Backpack - Skyscanner's Design System
+ *
+ * Copyright 2016 Skyscanner Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import BpkCarousel from "./src";
+
+export default BpkCarousel

packages/bpk-component-carousel/src/BpkCarousel-test.tsx

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+import { render, screen, getAllByRole } from '@testing-library/react';
+import { axe } from 'jest-axe';
+import userEvent from '@testing-library/user-event';
+import type { ReactNode } from 'react';
+
+import BpkCarousel from './BpkCarousel';
+
+
+describe('BpkCarousel', () => {
+  let images: ReactNode[]
+
+  const DemoImages = () => (
+    <img src="https://d2xf5gjipzd8cd.cloudfront.net/available/949043373/949043373_343x132.jpg" alt='' />
+  )
+
+  function generateDemoImages(count: number) {
+    return Array.from({ length: count }, (_, i) => (<DemoImages />));
+  }
+
+  type TestCase = [
+    expectedCount: 7 | 5 | 4 | 12,
+    actualCount: number,
+    props: React.ComponentProps<typeof BpkCarousel>,
+  ];
+
+  beforeAll(() => {
+
+    window.HTMLElement.prototype.scrollIntoView = jest.fn();
+
+    (window as any).IntersectionObserver = class IntersectionObserver {
+      observe = jest.fn();
+
+      disconnect = jest.fn();
+
+      unobserve = jest.fn();
+    };
+    images = [<DemoImages />, <DemoImages />, <DemoImages />, <DemoImages />, <DemoImages />];
+  });
+
+  it('should render correctly', () => {
+    const { asFragment } = render(<BpkCarousel images={images} />);
+
+    expect(asFragment()).toMatchSnapshot();
+  });
+
+  it.each<TestCase>([
+    [12, 10, { images: generateDemoImages(10) }],
+    [7, 5, { images: generateDemoImages(5) }],
+    [5, 3, { images: generateDemoImages(3) }],
+    [4, 2, { images: generateDemoImages(2) }],
+  ])(
+    'renders %i image(s) when there are %i image(s) available',
+    (expectedCount, actualCount, props) => {
+      render(<BpkCarousel {...props} />);
+
+      expect(screen.getByTestId('image-gallery-scroll-container').childElementCount).toBe(expectedCount);
+    },
+  );
+
+  it('renders only one image when only one available (no fake images for the infinite scroll)', async () => {
+    render(<BpkCarousel images={[images[0]]} />);
+
+    expect(screen.getByTestId('image-gallery-scroll-container').childElementCount).toBe(1);
+  });
+});

packages/bpk-component-carousel/src/BpkCarousel.d.ts

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+/*
+ * Backpack - Skyscanner's Design System
+ *
+ * Copyright 2022 Skyscanner Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { OnImageChangedHandler } from "./types";
+import type { ReactNode } from 'react';
+
+export type Props = {
+  images: ReactNode[]
+  initialImageIndex?: number;
+  onImageChanged?: OnImageChangedHandler
+};
+
+declare const BpkCarousel: {
+  ({ initialImageIndex, onImageChanged, ...rest }: Props): JSX.Element;
+  defaultProps: {
+    initialImageIndex: 0;
+    onImageChanged: null
+  };
+};
+export default BpkCarousel;

packages/bpk-component-carousel/src/BpkCarousel.tsx

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+import { useRef, useState } from 'react';
+
+
+import { useScrollToInitialImage } from './utils';
+import BpkCarouselContainer from './BpkCarouselContainer';
+import BpkSlidesIndicator from './BpkCarouselSlidesIndicator';
+import type { Props } from './types';
+
+const BpkCarousel = ({
+  images,
+  initialImageIndex = 0,
+  onImageChanged = null
+}: Props) => {
+  const [shownImageIndex, updateShownImageIndex] = useState(initialImageIndex);
+  const imagesRef = useRef<Array<HTMLElement | null>>([]);
+
+  useScrollToInitialImage(initialImageIndex, imagesRef);
+
+  return (
+    <>
+        <BpkCarouselContainer
+          images={images}
+          onVisible={updateShownImageIndex}
+          imagesRef={imagesRef}
+          onImageChanged={onImageChanged}
+        />
+      <BpkSlidesIndicator
+        length={images.length}
+        activeIndex={shownImageIndex}
+      />
+      </>
+  );
+};
+
+export default BpkCarousel;

packages/bpk-component-carousel/src/BpkCarouselContainer.module.css

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+/*
+ * Backpack - Skyscanner's Design System
+ * 
+ * Copyright 2016 Skyscanner Ltd
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+*/
+@keyframes bpk-keyframe-spin{100%{transform:rotate(1turn)}}.bpk-carousel-container{display:grid;width:100%;height:100%;grid:1fr / auto-flow 100%;border-radius:.75rem;overflow-x:auto;overflow-y:hidden;backface-visibility:hidden;overscroll-behavior:contain;scroll-snap-type:x mandatory;scrollbar-width:none;user-select:none}@media (max-width: 32.25rem){.bpk-carousel-container{border-radius:0}}.bpk-carousel-container::-webkit-scrollbar{display:none}

packages/bpk-component-carousel/src/BpkCarouselContainer.module.scss

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+@import '~bpk-mixins/index.scss';
+
+.bpk-carousel-container {
+  display: grid;
+  width: 100%;
+  height: 100%;
+  grid: 1fr / auto-flow 100%;
+  overflow-x: auto;
+  overflow-y: hidden;
+  backface-visibility: hidden;
+  overscroll-behavior: contain;
+  scroll-snap-type: x mandatory;
+  scrollbar-width: none;
+  user-select: none;
+
+  &::-webkit-scrollbar {
+    display: none;
+  }
+}

packages/bpk-component-carousel/src/BpkCarouselContainer.tsx

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+import type { MutableRefObject, ReactNode } from 'react';
+import { memo, useState } from 'react';
+
+import { cssModules } from '../../bpk-react-utils';
+
+import { useIntersectionObserver } from './utils';
+import STYLES from './BpkCarouselContainer.module.scss';
+import BpkCarouselImage from './BpkCarouselImage';
+import type { OnImageChangedHandler } from './types';
+
+const getClassName = cssModules(STYLES);
+
+type Props = {
+  images: ReactNode[];
+  onVisible: (visibleIndex: number) => void;
+  imagesRef: MutableRefObject<Array<HTMLElement | null>>;
+  onImageChanged: OnImageChangedHandler
+};
+
+const BpkScrollContainer = memo(({ images, imagesRef, onImageChanged, onVisible }: Props) => {
+  const [root, setRoot] = useState<HTMLElement | null>(null);
+  const observeImageChange = useIntersectionObserver(onVisible, {
+    root,
+    threshold: 0.5,
+  }, onImageChanged);
+  const observeCycleScroll = useIntersectionObserver(
+    (index) => {
+      const imageElement = imagesRef.current && imagesRef.current[index];
+      if (imageElement) {
+        imageElement.scrollIntoView({
+          block: 'nearest',
+          inline: 'start',
+        });
+      }
+    },
+    { root, threshold: 1 },
+  );
+
+  if (images.length === 1) {
+    return (
+      <div className={getClassName('bpk-carousel-container')} role="list" data-testid="image-gallery-scroll-container">
+        <BpkCarouselImage image={images[0]} index={0} />
+      </div>
+    );
+  }
+
+  return (
+    <div
+      className={getClassName('bpk-carousel-container')}
+      ref={setRoot}
+      data-testid="image-gallery-scroll-container"
+      role="list"
+    >
+      <BpkCarouselImage
+        image={images[images.length - 1]}
+        index={images.length - 1}
+        ref={(el) => {
+          observeCycleScroll(el);
+          observeImageChange(el);
+        }}
+      />
+      {images.map((image, index) => (
+        <BpkCarouselImage
+          // eslint-disable-next-line react/no-array-index-key
+          key={index}
+          image={image}
+          index={index}
+          ref={(el) => {
+            // eslint-disable-next-line no-param-reassign
+            imagesRef.current[index] = el;
+            observeImageChange(el);
+          }}
+        />
+      ))}
+      <BpkCarouselImage
+        image={images[0]}
+        index={0}
+        ref={(el) => {
+          observeCycleScroll(el);
+          observeImageChange(el);
+        }}
+      />
+    </div>
+  );
+});
+
+export default BpkScrollContainer;

packages/bpk-component-carousel/src/BpkCarouselImage.module.css

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+/*
+ * Backpack - Skyscanner's Design System
+ * 
+ * Copyright 2016 Skyscanner Ltd
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+*/
+@keyframes bpk-keyframe-spin{100%{transform:rotate(1turn)}}.bpk-carousel-image{display:inline-flex;width:100%;min-width:0;height:100%;min-height:0;justify-content:center;scroll-snap-align:start;scroll-snap-stop:always;isolation:isolate}.bpk-carousel-image img{max-width:100%;max-height:100%;border-radius:.75rem;object-fit:cover}@media (max-width: 32.25rem){.bpk-carousel-image img{border-radius:0;object-fit:contain}}

packages/bpk-component-carousel/src/BpkCarouselImage.module.scss

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+@import '~bpk-mixins/index.scss';
+
+.bpk-carousel-image {
+  display: inline-flex;
+  width: 100%;
+  min-width: 0;
+  height: 100%;
+  min-height: 0;
+  justify-content: center;
+  scroll-snap-align: start;
+  scroll-snap-stop: always;
+
+  /* helps with flickering when cycle scroll */
+  /* stylelint-disable-next-line order/properties-order */
+  isolation: isolate;
+
+  img {
+    max-width: 100%;
+    max-height: 100%;
+    border-radius: $bpk-border-radius-md;
+    object-fit: cover;
+
+    @include bpk-breakpoint-mobile {
+      border-radius: 0;
+      object-fit: contain;
+    }
+  }
+}