PX to Unitless line-height conversion and font fallbacks

fonts.scss

// I hate converting units so here's how to do 
// px to rem conversion with a fallback to px 
// for older browsers...

/**
 * Resize font from one type to another
 * @param  {[type]} $fontSize               the font size that you want
 * @param  {[type]} $toUnit:           rem  the unit you want to convert to
 * @param  {[type]} $fromUnitSpecific: px   default unit we're going to convert from (if you don't set it)
 *
 * Example 1:
 *    @include  font-size(22px);
 *    Result
 *    font-size: 22px; // generates a fallback for rems
 *    font-size: 2.2rem
 *
 * Example 2:
 *    @include  font-size(22em, "px");
 *    Result:
 *    font-size: 22px;
 *
 */
@mixin font-size($fontSize, $toUnit: rem, $fromUnitSpecific: px) {
    $currentUnit: unit($fontSize);
    $currentValue: get-value($fontSize);

    @if $currentUnit == "" {
        $currentUnit: $fromUnitSpecific;
    }

    @if $currentUnit == "px" {
        @if $toUnit == "rem" {
            font-size: unquote(($currentValue) + px);
            font-size: unquote(($currentValue / 10) + $toUnit);
        }
        @else if $toUnit == "em" {
            font-size: unquote(($currentValue / 10) + $toUnit);
        }
    }
    @else if $currentUnit == "rem" or $currentUnit == "em" {
        @if $toUnit == "px" {
            font-size: unquote(($currentValue * 10) + px);
        }
        @else {
            font-size: unquote(($currentValue) + $toUnit);
        }
    }
}

unitless.scss

// helper function to make sure the unit type (px, rem) 
// is removed we want just the raw value no unit
@function get-value($n) {
    @return $n / ($n * 0 + 1);
}

// pretty simple eh? 
@function get-line-height($font-size, $line-height) {
   @return get-value($line-height / $font-size);
}

// Usage: 
// Let's say you have an element that is going to be
// 26px font-size and you want a line-height of 32px
// you don't want to set 32px as the height because 
// that value will cascade down to child elements
// but if you're like me you're too lazy to do 
// math all the time...

.foo {
    font-size: 26px;
    line-height: get-line-height(26px, 32px); //1.23077
}