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Accessible Slideshow with React

The author discusses accessibility in-depth in the article "How to build a more accessible carousel or slider", with examples in vanilla JavaScript. It helps me a lot; please read it to get a thorough understanding. In the article below, I demonstrated how to create an accessible slideshow with React.

Or read the entire code on CodeSandbox.


Here's the screenshot of the example slideshow:

slideshow screenshot
slideshow screenshot

This is a simple one. The slideshow only has two buttons to navigate to the previous or the next slide. Every slide has one focusable element (a link).

I wrote the HTML(JSX) with some ARIA attributes at first.

<section aria-labelledby="carouselheading">
  <h2 id="carouselheading">The List of "The Matrix" Series</h2>

  {/* Add some introductions for this slideshow and visually hide it. */}
  <p className="sr-only">
    Carousel with one slide shown at a time. Use the Previous and Next buttons
    to navigate.
  </p>

  {/* The Previous button */}
  <button className="btn nav prev">
    <span className="sr-only">Previous One</span>
    <ChevronLeft size={64} />
  </button>

  {/* The group of slides */}
  <div className="slides">
    {MOVIES.map((movie, index) => (
      <div
        className="slide"
        key={movie.id}
        role="group"
        aria-label={`slide ${index + 1} of ${MOVIES.length}`}
        style={{
          "--translateX": `-${slideIndex * 100}%`,
        }}
      >
        <article>
          <h3>{movie.title}</h3>
          <p className="year">{movie.release_year}</p>
          <p className="director">
            Directed by <em>{movie.director}</em>
          </p>
          <a className="btn btn-primary" href={movie.link}>
            Details
          </a>
        </article>
        <figure>
          <img src={movie.poster} alt={`${movie.title} poster`} />
        </figure>
      </div>
    ))}
  </div>

  {/* The Next button */}
  <button className="btn nav next">
    <span className="sr-only">Next One</span>
    <ChevronRight size={64} />
  </button>
</section>
View the whole code on CodeSandbox

Although I used SVG icons for the previous and next buttons, I also wrote the text and wrapped it in elements labeled with sr-only classes to visually hide the text for accessibility.

For now, it is semantically accessible but not practical when used with a keyboard.

Bad slideshow screenshot
Bad slideshow screenshot

When we walk through the document with keyboard, the focus order depends on the order of the DOM. So, we need JavaScript to change the tabindex of the visually hidden slide items, also add aria-hidden to them from the accessibility devices. In this React app, I used useRef to access those div slide items.

const App = () => {
    const slidesRef = useRef([]);

    const makeSlidesAccessible = () => {
        // Hiding all the slides and their content
        slidesRef.current.forEach((slide) => {
            if (slide) {
                slide.setAttribute("aria-hidden", "true");
                slide.querySelector("a").setAttribute("tabindex", "-1");
            }
        });
    };

    useEffect(() => {
        makeSlidesAccessible();
    }, []);

    return (
        {/* omit */}
        {MOVIES.map((movie, index) => (
            <div
                ref={(element) => slidesRef.current.push(element)}
                className="slide"
                key={movie.id}
                role="group"
                aria-label={`slide ${index + 1} of ${MOVIES.length}`}
                style={{
                    "--translateX": `-${slideIndex * 100}%`
                }}
            >
            {/* omit */}
            </div>
        ))}
        {/* omit */}
    );
};

In the code above, besides setting aria-hidden to "true" for all the slide items, I made every a link within those items "unfocusable" by setting tabindex to "-1" to prevent the keyboard event from focusing on any hidden slides.

Next, by removing those added attributes, I made the current slide "visible" to accessibility devices and the a link focusable again.

const App = () => {
  const [slideIndex, setSlideIndex] = useState(0);
  const slidesRef = useRef([]);

  const makeSlidesAccessible = () => {
    // Hiding all the projects and their content
    slidesRef.current.forEach((slide) => {
      if (slide) {
        slide.setAttribute("aria-hidden", "true");
        slide.querySelector("a").setAttribute("tabindex", "-1");
      }
    });

    // Make sure the current slide not hide
    slidesRef.current[slideIndex].removeAttribute("aria-hidden");
    slidesRef.current[slideIndex]
      .querySelector("a")
      .removeAttribute("tabindex");
  };

  useEffect(() => {
    makeSlidesAccessible();
  }, [slideIndex]);

  return {
    /* omit */
  };
};

Then, everything works as expected.

Good slideshow screenshot
Good slideshow screenshot

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