@mui/material/internal/animate.js

function easeInOutSin(time) {
  return (1 + Math.sin(Math.PI * time - Math.PI / 2)) / 2;
}
export default function animate(property, element, to, options = {}, cb = () => {}) {
  const {
    ease = easeInOutSin,
    duration = 300 // standard
  } = options;
  let start = null;
  const from = element[property];
  let cancelled = false;
  const cancel = () => {
    cancelled = true;
  };
  const step = timestamp => {
    if (cancelled) {
      cb(new Error('Animation cancelled'));
      return;
    }
    if (start === null) {
      start = timestamp;
    }
    const time = Math.min(1, (timestamp - start) / duration);
    element[property] = ease(time) * (to - from) + from;
    if (time >= 1) {
      requestAnimationFrame(() => {
        cb(null);
      });
      return;
    }
    requestAnimationFrame(step);
  };
  if (from === to) {
    cb(new Error('Element already at target position'));
    return cancel;
  }
  requestAnimationFrame(step);
  return cancel;
}