@material-ui/core/es/transitions/utils.js

export const reflow = node => node.scrollTop;
export function getTransitionProps(props, options) {
  const {
    timeout,
    style = {}
  } = props;
  return {
    duration: style.transitionDuration || typeof timeout === 'number' ? timeout : timeout[options.mode] || 0,
    delay: style.transitionDelay
  };
}