locomotive-boilerplate/assets/styles/tools/_functions.scss

// ==========================================================================
// Tools / Functions
// ==========================================================================

// Converts the given pixel value to its EM quivalent.
//
// @param  {Number} $size                     - The pixel value to convert.
// @param  {Number} $base [$font-size] - The assumed base font size.
// @return {Number} Scalable pixel value in EMs.

@function em($size, $base: $font-size) {
    @if (type-of($size) == number) {
        @if (unit($size) != "px") {
            @error "`#{$size}` needs to be a pixel value.";
        }
    } @else {
        @error "`#{$size}` needs to be a number.";
    }

    @if (type-of($base) == number) {
        @if (unit($base) != "px") {
            @error "`#{$base}` needs to be a pixel value.";
        }
    } @else {
        @error "`#{$base}` needs to be a number.";
    }

    @return ($size / $base) * 1em;
}

// Converts the given pixel value to its REM quivalent.
//
// @param  {Number} $size                     - The pixel value to convert.
// @param  {Number} $base [$font-size] - The assumed base font size.
// @return {Number} Scalable pixel value in REMs.

@function rem($size, $base: $font-size) {
    @if (type-of($size) == number) {
        @if (unit($size) != "px") {
            @error "`#{$size}` needs to be a pixel value.";
        }
    } @else {
        @error "`#{$size}` needs to be a number.";
    }

    @if (type-of($base) == number) {
        @if (unit($base) != "px") {
            @error "`#{$base}` needs to be a pixel value.";
        }
    } @else {
        @error "`#{$base}` needs to be a number.";
    }

    @return ($size / $base) * 1rem;
}

// A function helper to avoid having to type `map-get($layers, ...)`
//
// @link on http://css-tricks.com/handling-z-index/
// @param  {string} $layer The name of the z-index
// @param  {number} $var   The modifier if needed
// @return {number}        The corresponding z-index based on the $layers var

@function z($layer, $var: 0) {
    @if not map-has-key($layers, $layer) {
        @error "No z-index found in $layers map for `#{$layer}`. Property omitted.";
    }

    $value: map-get($layers, $layer);
    @return $value + $var;
}

// Converts a number to a percentage.
//
// @alias  percentage()
// @link   http://sassdoc.com/annotations/#alias
// @param  {Number} $number - The value to convert.
// @return {Number} A percentage.

@function span($number) {
    @return percentage($number);
}

// Checks if a list contains a value(s).
//
// @link   https://github.com/thoughtbot/bourbon/blob/master/core/bourbon/validators/_contains.scss
// @param  {List} $list   - The list to check against.
// @param  {List} $values - A single value or list of values to check for.
// @return {Boolean}
// @access private

@function list-contains(
    $list,
    $values...
) {
    @each $value in $values {
        @if type-of(index($list, $value)) != "number" {
            @return false;
        }
    }

    @return true;
}

// Resolve whether a rule is important or not.
//
// @param  {Boolean}     $flag - Whether a rule is important (TRUE) or not (FALSE).
// @return {String|Null} Returns `!important` or NULL.

@function important($flag: false) {
    @if ($flag == true) {
        @return !important;
    } @elseif ($important == false) {
        @return null;
    } @else {
        @error "`#{$flag}` needs to be `true` or `false`.";
    }
}

// Determine if the current context is for a WYSIWYG editor.
//
// @requires {String} $context - The global context of the stylesheet.
// @return   {Boolean} If the $context is set to "editor".

@function is-editor() {
    @return ('editor' == $context);
}

// Determine if the current context is for the front-end.
//
// @requires {String} $context - The global context of the stylesheet.
// @return   {Boolean} If the $context is set to "frontend".

@function is-frontend() {
    @return ('frontend' == $context);
}

$context: 'frontend' !default;