Number transition

import type { CSSProperties } from "react";
import { NumberTransition } from "./components/stepkit/NumberTransition";
import "./components/stepkit/styles.css";

const themeStyle = {"--stepkit-bg":"#f7f7f8","--stepkit-surface":"#ffffff","--stepkit-surface-muted":"#f0f0f3","--stepkit-fg":"#17181c","--stepkit-muted":"#626572","--stepkit-border":"#e3e4e9","--stepkit-border-strong":"#c8cad3","--stepkit-code":"#f1f1f4","--stepkit-shadow":"0 20px 60px rgba(31, 26, 64, .10)","--stepkit-accent":"#6950df","--stepkit-accent-strong":"#5137c7","--stepkit-accent-soft":"#eeeafd","--stepkit-accent-on-soft":"#5137c7","--stepkit-accent-text":"#ffffff","--stepkit-error":"#b43145","--stepkit-placeholder":"#626572","--stepkit-radius":"16px","--stepkit-space":"16px","--stepkit-control-height":"44px","--stepkit-font-sans":"Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, \"Segoe UI\", sans-serif"} as CSSProperties;

export default function Example() {
  return (
    <div className="stepkit-theme" data-stepkit-preset="modern" style={themeStyle}>
      <NumberTransition
      value={940}
      startValue={0}
      direction={"up"}
      paused={false}
      />
    </div>
  );
}

/*
 * Stepkit 0.2.0
 * Copyright (c) 2026 Vladislav Stepanov
 *
 * Original Stepkit portions in this release are licensed under the MIT License. Adapted portions identify their upstream licence and copyright in the copied source and in `NOTICE-MAGICUI.md` where applicable.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 *
 * # Magic UI MIT licence snapshot
 *
 * Source: https://github.com/magicuidesign/magicui/blob/main/LICENSE.md
 * Repository snapshot reviewed at commit: `bca54ab2730216c91e3a732f2af08e49c7ddebd4`
 * Retrieved through Firecrawl: 2026-09-19
 *
 * MIT License
 *
 * Copyright (c) Magic UI
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
"use client";

import { useEffect, useMemo, useState, type ComponentPropsWithoutRef } from "react";
import "./styles.css";

/**
 * Adapted behaviour reference: Magic UI Number Ticker, MIT License.
 * Copyright (c) Magic UI. Source and licence evidence: provenance/.
 * Stepkit uses a local requestAnimationFrame implementation without motion.
 */
export interface NumberTransitionProps extends ComponentPropsWithoutRef<"span"> {
  value: number;
  startValue?: number;
  direction?: "up" | "down";
  delay?: number;
  duration?: number;
  decimalPlaces?: number;
  paused?: boolean;
}

function clampNumber(value: number, fallback: number) {
  return Number.isFinite(value) ? value : fallback;
}

function formatNumber(value: number, decimalPlaces: number) {
  return new Intl.NumberFormat("en-US", {
    minimumFractionDigits: decimalPlaces,
    maximumFractionDigits: decimalPlaces,
  }).format(Number(value.toFixed(decimalPlaces)));
}

export function NumberTransition({
  value,
  startValue = 0,
  direction = "up",
  delay = 0,
  duration = 900,
  decimalPlaces = 0,
  paused = false,
  className = "",
  ...props
}: NumberTransitionProps) {
  const target = clampNumber(value, 0);
  const origin = clampNumber(startValue, 0);
  const decimals = Math.min(6, Math.max(0, Math.trunc(clampNumber(decimalPlaces, 0))));
  const wait = Math.min(30_000, Math.max(0, clampNumber(delay, 0) * 1000));
  const span = Math.min(20_000, Math.max(100, clampNumber(duration, 900)));
  const initial = direction === "down" ? target : origin;
  const finalValue = direction === "down" ? origin : target;
  const [current, setCurrent] = useState(initial);
  const [reducedMotion, setReducedMotion] = useState(false);

  useEffect(() => {
    if (typeof window === "undefined" || typeof window.matchMedia !== "function") return;
    const query = window.matchMedia("(prefers-reduced-motion: reduce)");
    const update = () => setReducedMotion(query.matches);
    update();
    query.addEventListener?.("change", update);
    return () => query.removeEventListener?.("change", update);
  }, []);

  useEffect(() => {
    setCurrent(initial);
    if (paused || reducedMotion || typeof window === "undefined") return;
    let frame = 0;
    let timer: ReturnType<typeof setTimeout> | undefined;
    const startedAt = performance.now() + wait;
    const tick = (now: number) => {
      const progress = Math.min(1, Math.max(0, (now - startedAt) / span));
      const eased = 1 - Math.pow(1 - progress, 3);
      setCurrent(initial + (finalValue - initial) * eased);
      if (progress < 1) frame = window.requestAnimationFrame(tick);
    };
    if (wait > 0) timer = setTimeout(() => { frame = window.requestAnimationFrame(tick); }, wait);
    else frame = window.requestAnimationFrame(tick);
    return () => { if (timer) clearTimeout(timer); if (frame) window.cancelAnimationFrame(frame); };
  }, [finalValue, initial, paused, reducedMotion, span, wait]);

  const output = useMemo(() => formatNumber(paused || reducedMotion ? finalValue : current, decimals), [current, decimals, finalValue, paused, reducedMotion]);
  return <span className={`stepkit stepkit-number-transition${className ? ` ${className}` : ""}`} data-direction={direction} data-paused={paused} {...props}>{output}</span>;
}

export default NumberTransition;