ionic-framework/core/src/utils/media.ts

export const SIZE_TO_MEDIA: any = {
  'xs': '(min-width: 0px)',
  'sm': '(min-width: 576px)',
  'md': '(min-width: 768px)',
  'lg': '(min-width: 992px)',
  'xl': '(min-width: 1200px)',
};

// Check if the window matches the media query
// at the breakpoint passed
// e.g. matchBreakpoint('sm') => true if screen width exceeds 576px
export const matchBreakpoint = (breakpoint: string | undefined) => {
  if (breakpoint === undefined || breakpoint === '') {
    return true;
  }
  if ((window as any).matchMedia) {
    const mediaQuery = SIZE_TO_MEDIA[breakpoint];
    return window.matchMedia(mediaQuery).matches;
  }
  return false;
};