.sass version of rem converter @https://github.com/pierreburel/sass-rem/blob/master/_rem.scss

_rem.sass

// .sass version of rem converter @https://github.com/pierreburel/sass-rem/blob/master/_rem.scss

$rem-baseline: 16px !default
$rem-fallback: true !default
$rem-px-only: false !default

// list-separator polyfill by Hugo Giraudel (https://sass-compatibility.github.io/#list_separator_function)
@function rem-separator($list)
    @if function-exists("list-separator") == true
        @return list-separator($list)
    $test-list: ()
    @each $item in $list
        $test-list: append($test-list, $item, space)
    @return if($test-list == $list, space, comma)

=rem-baseline($zoom: 100%)
    font-size: $zoom / 16px * $rem-baseline

@function rem-convert($to, $values...)
    $result: ()
    $separator: rem-separator($values)
    @each $value in $values
        @if type-of($value) == "number" and unit($value) == "rem" and $to == "px"
            $result: append($result, $value / 1rem * $rem-baseline, $separator)
        @else if type-of($value) == "number" and unit($value) == "px" and $to == "rem"
            $result: append($result, $value / ($rem-baseline / 1rem), $separator)
        @else if type-of($value) == "list"
            $result: append($result, rem-convert($to, $value...), $separator)
        @else
            $result: append($result, $value, $separator)
    @return if(length($result) == 1, nth($result, 1), $result)

@function rem($values...)
    @if $rem-px-only
        @return rem-convert(px, $values...)
    @else
        @return rem-convert(rem, $values...)

=rem($properties, $values...)
    @if type-of($properties) == "map"
        @each $property in map-keys($properties)
            +rem($property, map-get($properties, $property))
    @else
        @each $property in $properties
            @if $rem-fallback or $rem-px-only
                #{$property}: rem-convert(px, $values...)
            @if not $rem-px-only
                #{$property}: rem-convert(rem, $values...)