google-map-react/develop/utils/isReferentiallyTransparentFunctionComponent.js

const isClassComponent = Component => Boolean(
  Component &&
  Component.prototype &&
  typeof Component.prototype.isReactComponent === 'object'
);

const isReferentiallyTransparentFunctionComponent = Component => Boolean(
  typeof Component === 'function' &&
  !isClassComponent(Component) &&
  !Component.defaultProps &&
  !Component.contextTypes &&
  !Component.propTypes
);

export default isReferentiallyTransparentFunctionComponent;