Marquee

<div class="kodza-marquee">
  <div class="kodza-marquee__track">
    <span class="kodza-marquee__item">Copy</span>
    <span class="kodza-marquee__item">Paste</span>
    <span class="kodza-marquee__item">Ship</span>
    <span class="kodza-marquee__item">Go home early</span>
  </div>
</div>

<div class="kodza-marquee kodza-marquee--reverse">
  <div class="kodza-marquee__track">
    <span class="kodza-marquee__item">No build step</span>
    <span class="kodza-marquee__item">No npm install</span>
    <span class="kodza-marquee__item">No drama</span>
  </div>
</div>

/* Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license */
/* Kodza — Marquee
   An endless ticker that never jumps: the script copies the words just enough times to
   fill the width, and the loop restarts exactly one copy later. It slows to a halt
   under the pointer, and fades out at both edges.
   Variant: --reverse (the other way).
   Everything is tuned with the --kz-marquee-* variables. */
.kodza-marquee {
  --kz-marquee-speed: 60; /* pixels per second */
  --kz-marquee-gap: 0.6em;
  --kz-marquee-dot: 0.16em;
  --kz-marquee-fade: 8%;

  /* Always the full available width, and never wider: its endless content must not
     stretch a flex or grid parent (which would make the marquee grow forever) */
  width: 100%;
  min-width: 0;
  contain: inline-size;
  overflow: hidden;
  white-space: nowrap;
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 var(--kz-marquee-fade), #000 calc(100% - var(--kz-marquee-fade)), transparent);
  mask-image: linear-gradient(90deg, transparent, #000 var(--kz-marquee-fade), #000 calc(100% - var(--kz-marquee-fade)), transparent);
}

.kodza-marquee__track {
  display: inline-flex;
  will-change: transform;
}

.kodza-marquee__item {
  display: inline-flex;
  align-items: center;
}

/* A round dot between the words, drawn rather than typed: perfectly round and centred in any font */
.kodza-marquee__item::after {
  content: "";
  flex-shrink: 0;
  width: var(--kz-marquee-dot);
  height: var(--kz-marquee-dot);
  min-width: 4px;
  min-height: 4px;
  margin: 0 var(--kz-marquee-gap);
  border-radius: 50%;
  background: currentColor;
}

.kodza-marquee.is-ready .kodza-marquee__track {
  animation: kodza-marquee-loop var(--kz-marquee-duration, 20s) linear infinite;
}

.kodza-marquee--reverse.is-ready .kodza-marquee__track {
  animation-direction: reverse;
}

@keyframes kodza-marquee-loop {
  to { transform: translateX(calc(-1 * var(--kz-marquee-distance, 50%))); }
}

@media (prefers-reduced-motion: reduce) {
  .kodza-marquee.is-ready .kodza-marquee__track {
    animation: none;
  }
}

/* kodza-guard 68dfe064dd32 — generated by Kodza, do not edit.
   Theme guard: keeps a site's own CSS (WordPress themes, Bootstrap, CSS resets…) off this
   component. :not(#_) is always true and weighs as much as an id, so these lines win over
   theme rules made of classes and tags. Customise the component through its --kz-* variables. */

/* What the browser gives, on everything the component leaves to it */

.kodza-marquee:not(#_),
.kodza-marquee__track:not(#_),
.kodza-marquee__item:not(#_) {
  box-sizing: revert;
}

.kodza-marquee__item:not(#_)::after {
  box-sizing: revert;
}

// Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license
// Kodza — Marquee
// Copies the words until they fill the width twice (copies are hidden from screen
// readers), then loops over exactly one set, at a constant speed in pixels per second.
// Under the pointer it eases to a stop instead of freezing, and starts again the same way.
(() => {
  const SELECTOR = '.kodza-marquee';
  const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  // One instance. Everything it starts is tied to `signal`, so kodza:destroy stops it all
  function mount(root, signal) {
    const track = root.querySelector('.kodza-marquee__track');
    if (!track) return;
    const original = [...track.children];

    const fill = () => {
      track.querySelectorAll('[data-copy]').forEach((copy) => copy.remove());
      const setWidth = track.scrollWidth;
      if (!setWidth) return;
      // Enough copies to cover the width plus one set (capped, in case the width is off)
      for (let filled = setWidth, n = 0; filled < root.clientWidth + setWidth && n < 50; filled += setWidth, n++) {
        original.forEach((item) => {
          const copy = item.cloneNode(true);
          copy.dataset.copy = '';
          copy.setAttribute('aria-hidden', 'true');
          track.append(copy);
        });
      }
      const speed = parseFloat(getComputedStyle(root).getPropertyValue('--kz-marquee-speed')) || 60;
      root.style.setProperty('--kz-marquee-distance', `${setWidth}px`);
      root.style.setProperty('--kz-marquee-duration', `${setWidth / speed}s`);
    };

    // is-ready comes with the mount, so the loop is held here until the fonts are in (measured
    // with a fallback font, it would jump when they swap)
    let filled = false;
    track.style.animationPlayState = 'paused';
    document.fonts.ready.then(() => {
      if (signal.aborted) return;
      fill();
      filled = true;
      track.style.animationPlayState = '';
    });
    // Refill only when the available width really changes
    let width = 0;
    const observer = new ResizeObserver(([entry]) => {
      if (Math.abs(entry.contentRect.width - width) < 1) return;
      width = entry.contentRect.width;
      if (filled) fill();
    });
    observer.observe(root);
    signal.addEventListener('abort', () => observer.disconnect());
    if (reduceMotion) return;

    // Slow down and speed up smoothly, by easing the animation's playback rate
    let rate = 1;
    let target = 1;
    let frame = null;
    const ease = () => {
      if (signal.aborted) return;
      rate += (target - rate) * 0.08;
      if (Math.abs(target - rate) < 0.01) rate = target;
      track.getAnimations().forEach((animation) => (animation.playbackRate = rate));
      frame = rate === target ? null : requestAnimationFrame(ease);
    };
    const setTarget = (value) => {
      target = value;
      if (!frame) frame = requestAnimationFrame(ease);
    };
    root.addEventListener('pointerenter', () => setTarget(0), { signal });
    root.addEventListener('pointerleave', () => setTarget(1), { signal });
  }

  // Kodza lifecycle, the same in every component: `kodza:init` starts the instances inside
  // event.detail.root (the whole page by default), `kodza:destroy` stops them and puts their
  // markup back. For themes and apps that swap content without a page load.
  const instances = new WeakMap();
  const find = (scope = document) => [scope, ...scope.querySelectorAll(SELECTOR)].filter((el) => el.matches?.(SELECTOR));
  const init = (scope) => find(scope).forEach((root) => {
    if (root.classList.contains('is-ready')) return; // already running, maybe from another copy of this script
    const controller = new AbortController();
    instances.set(root, { controller, html: root.innerHTML, attrs: [...root.attributes].map((a) => [a.name, a.value]) });
    mount(root, controller.signal);
    root.classList.add('is-ready');
  });
  const destroy = (scope) => find(scope).forEach((root) => {
    const instance = instances.get(root);
    if (!instance) return;
    instances.delete(root);
    instance.controller.abort();
    [...root.attributes].forEach((a) => root.removeAttribute(a.name));
    instance.attrs.forEach(([name, value]) => root.setAttribute(name, value));
    root.innerHTML = instance.html;
  });
  document.addEventListener('kodza:init', (event) => init(event.detail?.root));
  document.addEventListener('kodza:destroy', (event) => destroy(event.detail?.root));
  init();
  // Loaded in <head>, the script runs before the markup exists: once more when it is parsed
  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', () => init(), { once: true });
})();

'use client';
// Kodza — Marquee, for React. From https://kodza.dev/components/scrolling-text-loop/
// Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license
// Next to this file: scrolling-text-loop.css and scrolling-text-loop.js, the component's CSS and JS from Kodza, as they are.
// Yours to edit: the markup is plain JSX below.
// The script changes this markup once React has rendered it (it adds layers, splits text, moves
// nodes), so React must not patch it afterwards. When a prop changes, the key gives React a fresh
// element: kodza:destroy stops the script on the old one, kodza:init starts it on the new one.
import { useRef, useEffect, type ComponentPropsWithoutRef, type ComponentRef, type CSSProperties } from 'react';
import './scrolling-text-loop.css';

type Variant = "reverse";

export type MarqueeProps = Omit<ComponentPropsWithoutRef<'div'>, "children" | "variant" | "vars"> & {
  /** Modifier class(es): .kodza-marquee--reverse */
  variant?: Variant | Variant[];
  /** Settings, as CSS variables on the root */
  vars?: {
    /** pixels per second — default: 60 */
    "--kz-marquee-speed"?: string | number;
    /** default: 0.6em */
    "--kz-marquee-gap"?: string | number;
    /** default: 0.16em */
    "--kz-marquee-dot"?: string | number;
    /** default: 8% */
    "--kz-marquee-fade"?: string | number;
  };
  className?: string;
};

export function Marquee({ variant, vars, className, style, ...rest }: MarqueeProps) {
  const ref = useRef<ComponentRef<'div'>>(null);
  const classes = ["kodza-marquee", ...([] as string[]).concat(variant ?? []).map((v) => `kodza-marquee--${v}`), className].filter(Boolean).join(' ');
  // Everything the markup is made of: when it changes, React gets a fresh element (see the top)
  const key = JSON.stringify([classes, vars, style, rest]);

  // Starts the script on this element once React has rendered it, stops it when it goes
  useEffect(() => {
    const root = ref.current;
    let live = true;
    // @ts-ignore: a plain script, no types to find
    import('./scrolling-text-loop.js').then(() => {
      if (live) document.dispatchEvent(new CustomEvent('kodza:init', { detail: { root } }));
    });
    return () => {
      live = false;
      document.dispatchEvent(new CustomEvent('kodza:destroy', { detail: { root } }));
    };
  }, [key]);

  return (
    <div key={key} {...rest} className={classes} style={{ ...vars, ...style } as CSSProperties} ref={ref}>
      <div className="kodza-marquee__track">
        <span className="kodza-marquee__item">Copy</span>
        {' '}
        <span className="kodza-marquee__item">Paste</span>
        {' '}
        <span className="kodza-marquee__item">Ship</span>
        {' '}
        <span className="kodza-marquee__item">Go home early</span>
      </div>
    </div>
  );
}