react-dates/src/utils/getResponsiveContainerStyles.js

A responsive and accessible date range picker component built with React

import { ANCHOR_LEFT } from '../../constants';

export default function getResponsiveContainerStyles(
  anchorDirection,
  currentOffset,
  containerEdge,
  margin,
) {
  const windowWidth = typeof window !== 'undefined' && window.innerWidth;
  const calculatedOffset =
    anchorDirection === ANCHOR_LEFT ? windowWidth - containerEdge : containerEdge;
  const calculatedMargin = margin || 0;

  return {
    [anchorDirection]: Math.min(currentOffset + calculatedOffset - calculatedMargin, 0),
  };
}