Responsive CSS font-size in SASS

responsive-font-size.sass

@mixin responsive-font-size($min-size, $max-size, $min-break, $max-break) {
  font-size: calc(
    #{$min-size} + #{strip-units($max-size - $min-size)} *
    ((100vw - #{$min-break}) / #{strip-units($max-break - $min-break)})
  );

  @media screen and (max-width: $min-break) {
    & {
      font-size: $min-size;
    }
  }

  @media screen and (min-width: $max-break) {
    & {
      font-size: $max-size;
    }
  }
}

// This is more a hack than anything else, how would one do this properly?
@function strip-units($value) {
  @return $value / ($value * 0 + 1);
}