Accessing CSS "breakpoints" via JS

// Le Sass
// This goes through media queries and puts value in pseudo element as a js-hook
$_query-list: palm-and-down hand-and-up lap-and-up desk-and-up;
@each $mq in $_query-list {
  @include media-query($mq) {
    body:before { content: "#{$mq}"; display: none; }
  }
}

// Le JavaScript
// Retrieve breakpoint in JS like so:
var breakpoint = getComputedStyle(document.body, ':before').content;