@mui/material/styles/createTransitions.js

// Follow https://material.google.com/motion/duration-easing.html#duration-easing-natural-easing-curves
// to learn the context in which each easing should be used.
export const easing = {
  // This is the most common easing curve.
  easeInOut: 'cubic-bezier(0.4, 0, 0.2, 1)',
  // Objects enter the screen at full velocity from off-screen and
  // slowly decelerate to a resting point.
  easeOut: 'cubic-bezier(0.0, 0, 0.2, 1)',
  // Objects leave the screen at full velocity. They do not decelerate when off-screen.
  easeIn: 'cubic-bezier(0.4, 0, 1, 1)',
  // The sharp curve is used by objects that may return to the screen at any time.
  sharp: 'cubic-bezier(0.4, 0, 0.6, 1)'
};

// Follow https://m2.material.io/guidelines/motion/duration-easing.html#duration-easing-common-durations
// to learn when use what timing
export const duration = {
  shortest: 150,
  shorter: 200,
  short: 250,
  // most basic recommended timing
  standard: 300,
  // this is to be used in complex animations
  complex: 375,
  // recommended when something is entering screen
  enteringScreen: 225,
  // recommended when something is leaving screen
  leavingScreen: 195
};
function formatMs(milliseconds) {
  return `${Math.round(milliseconds)}ms`;
}
function getAutoHeightDuration(height) {
  if (!height) {
    return 0;
  }
  const constant = height / 36;

  // https://www.desmos.com/calculator/vbrp3ggqet
  return Math.min(Math.round((4 + 15 * constant ** 0.25 + constant / 5) * 10), 3000);
}
export default function createTransitions(inputTransitions) {
  const mergedEasing = {
    ...easing,
    ...inputTransitions.easing
  };
  const mergedDuration = {
    ...duration,
    ...inputTransitions.duration
  };
  const create = (props = ['all'], options = {}) => {
    const {
      duration: durationOption = mergedDuration.standard,
      easing: easingOption = mergedEasing.easeInOut,
      delay = 0,
      ...other
    } = options;
    if (process.env.NODE_ENV !== 'production') {
      const isString = value => typeof value === 'string';
      const isNumber = value => !Number.isNaN(parseFloat(value));
      if (!isString(props) && !Array.isArray(props)) {
        console.error('MUI: Argument "props" must be a string or Array.');
      }
      if (!isNumber(durationOption) && !isString(durationOption)) {
        console.error(`MUI: Argument "duration" must be a number or a string but found ${durationOption}.`);
      }
      if (!isString(easingOption)) {
        console.error('MUI: Argument "easing" must be a string.');
      }
      if (!isNumber(delay) && !isString(delay)) {
        console.error('MUI: Argument "delay" must be a number or a string.');
      }
      if (typeof options !== 'object') {
        console.error(['MUI: Secong argument of transition.create must be an object.', "Arguments should be either `create('prop1', options)` or `create(['prop1', 'prop2'], options)`"].join('\n'));
      }
      if (Object.keys(other).length !== 0) {
        console.error(`MUI: Unrecognized argument(s) [${Object.keys(other).join(',')}].`);
      }
    }
    return (Array.isArray(props) ? props : [props]).map(animatedProp => `${animatedProp} ${typeof durationOption === 'string' ? durationOption : formatMs(durationOption)} ${easingOption} ${typeof delay === 'string' ? delay : formatMs(delay)}`).join(',');
  };
  return {
    getAutoHeightDuration,
    create,
    ...inputTransitions,
    easing: mergedEasing,
    duration: mergedDuration
  };
}