backnotprop__plannotator/packages/ui/components/TextShimmer.tsx

import React, { useMemo, type JSX } from 'react';
import { motion, useReducedMotion } from 'motion/react';

export interface TextShimmerProps {
  children: string;
  as?: React.ElementType;
  className?: string;
  duration?: number;
  spread?: number;
}

function TextShimmerComponent({
  children,
  as: Component = 'span',
  className,
  duration = 2,
  spread = 2,
}: TextShimmerProps) {
  const shouldReduceMotion = useReducedMotion();
  const MotionComponent = motion.create(
    Component as keyof JSX.IntrinsicElements
  );

  const dynamicSpread = useMemo(() => {
    return children.length * spread;
  }, [children, spread]);

  return (
    <MotionComponent
      className={[
        'relative inline-block bg-[length:250%_100%,auto] bg-clip-text',
        'text-transparent [--base-color:#a1a1aa] [--base-gradient-color:#000]',
        '[background-repeat:no-repeat,padding-box] [--bg:linear-gradient(90deg,#0000_calc(50%-var(--spread)),var(--base-gradient-color),#0000_calc(50%+var(--spread)))]',
        'dark:[--base-color:#71717a] dark:[--base-gradient-color:#ffffff] dark:[--bg:linear-gradient(90deg,#0000_calc(50%-var(--spread)),var(--base-gradient-color),#0000_calc(50%+var(--spread)))]',
        className,
      ]
        .filter(Boolean)
        .join(' ')}
      initial={shouldReduceMotion ? false : { backgroundPosition: '100% center' }}
      animate={shouldReduceMotion ? undefined : { backgroundPosition: '0% center' }}
      transition={shouldReduceMotion ? undefined : {
        repeat: Infinity,
        duration,
        ease: 'linear',
      }}
      style={
        {
          '--spread': `${dynamicSpread}px`,
          backgroundImage: shouldReduceMotion
            ? 'linear-gradient(var(--base-color), var(--base-color))'
            : 'var(--bg), linear-gradient(var(--base-color), var(--base-color))',
        } as React.CSSProperties
      }
    >
      {children}
    </MotionComponent>
  );
}

export const TextShimmer = React.memo(TextShimmerComponent);