Javascript to check (Bootstrap 4) breakpoints based on CSS variables

matchBreakpoint.js

function matchBreakpoint(breakpoint) {
    var value = window.getComputedStyle(document.documentElement).getPropertyValue('--breakpoint-' + breakpoint);
    return window.matchMedia("(min-width: " + value + ")").matches;
}

// Example:
// matchBreakpoint('md') ? 'its md' : 'meh';

// You can also use this if you provide CSS variables with --breakpoint-[breakpoint] in your custom CSS or on other frameworks.
// It's simple to adapt.