Function calculateMomentum

src/components/utils/thumbnailMomentum.ts:93–139

(config: MomentumConfig)

 * Calculate the full momentum result for a thumbnail swipe
 */
export function calculateMomentum(config: MomentumConfig): MomentumResult {
  const {
    velocity,
    direction,
    isVertical,
    currentTranslate,
    scrollSize,
    wrapperSize,
    slideDuration,
    emptySpaceMargin = 0,
    momentumMultiplier = 150,
  } = config;

  // Calculate momentum distance and direction
  const momentumDistance = calculateMomentumDistance(
    velocity,
    momentumMultiplier
  );
  const directionSign = getMomentumDirection(direction, isVertical);
  const momentum = momentumDistance * directionSign;

  // Calculate target translate with momentum
  let targetTranslate = currentTranslate + momentum;

  // Calculate max scroll and clamp
  const maxScroll = scrollSize - wrapperSize + emptySpaceMargin;
  if (maxScroll > 0) {
    targetTranslate = clampTranslate(
      targetTranslate,
      maxScroll,
      emptySpaceMargin
    );
  }

  // Calculate transition
  const transitionDuration = calculateTransitionDuration(
    velocity,
    slideDuration
  );
  const transitionStyle = `all ${transitionDuration}ms ${MOMENTUM_EASING}`;

  return {
    targetTranslate,
    transitionDuration,
    transitionStyle,
  };
}