foundation-sites/scss/util/_value.scss

// Foundation for Sites by ZURB
// foundation.zurb.com
// Licensed under MIT Open Source

////
/// @group functions
////

/// Determine if a value is not falsey, in CSS terms. Falsey values are `null`, `none`, `0` with any unit, or an empty list.
///
/// @param {Mixed} $val - Value to check.
///
/// @returns {Boolean} `true` if `$val` is not falsey.
@function has-value($val) {
  @if $val == null or $val == none {
    @return false;
  }
  @if type-of($val) == 'number' and strip-unit($val) == 0 {
    @return false;
  }
  @if type-of($val) == 'list' and length($val) == 0 {
    @return false;
  }
  @return true;
}

/// Determine a top/right/bottom/right value on a padding, margin, etc. property, no matter how many values were passed in. Use this function if you need to know the specific side of a value, but don't know if the value is using a shorthand format.
///
/// @param {List|Number} $val - Value to analyze. Should be a shorthand sizing property, e.g. "1em 2em 1em"
/// @param {Keyword} $side - Side to return. Should be `top`, `right`, `bottom`, or `left`.
///
/// @returns {Number} A single value based on `$val` and `$side`.
@function get-side($val, $side) {
  $length: length($val);

  @if $length == 1 {
    @return $val;
  }
  @if $length == 2 {
    @return map-get((
      top: nth($val, 1),
      bottom: nth($val, 1),
      left: nth($val, 2),
      right: nth($val, 2),
    ), $side);
  }
  @if $length == 3 {
    @return map-get((
      top: nth($val, 1),
      left: nth($val, 2),
      right: nth($val, 2),
      bottom: nth($val, 3),
    ), $side);
  }
  @if $length == 4 {
    @return map-get((
      top: nth($val, 1),
      right: nth($val, 2),
      bottom: nth($val, 3),
      left: nth($val, 4),
    ), $side);
  }
}

/// Given border $val, find a specific element of the border, which is $elem. The possible values for $elem are width, style, and color.
///
/// @param {List} $val - Border value to find a value in.
/// @param {Keyword} $elem - Border component to extract.
///
/// @returns {Mixed} If the value exists, returns the value. If the value is not in the border definition, the function will return a 0px width, solid style, or black border.
@function get-border-value($val, $elem) {
  // Find the width, style, or color and return it
  @each $v in $val {
    $type: type-of($v);
    @if $elem == width and $type == 'number' {
      @return $v;
    }
    @if $elem == style and $type == 'string' {
      @return $v;
    }
    @if $elem == color and $type == 'color' {
      @return $v;
    }
  }

  // Defaults
  $defaults: (
    width: 0,
    style: solid,
    color: #000,
  );

  @return map-get($defaults, $elem);
}

/// Finds a value in a nested map.
/// @link https://css-tricks.com/snippets/sass/deep-getset-maps/ Deep Get/Set in Maps
///
/// @param {Map} $map - Map to pull a value from.
/// @param {String} $keys... - Keys to use when looking for a value.
/// @returns {Mixed} The value found in the map.
@function map-deep-get($map, $keys...) {
  @each $key in $keys {
    $map: map-get($map, $key);
  }
  @return $map;
}

/// Casts a map into a list.
/// @link http://hugogiraudel.com/2014/04/28/casting-map-into-list/
///
/// @param {Map} $map - Map to pull a value from.
///
/// @returns {List} Depending on the flag, returns either $keys or $values or both.
@function map-to-list($map, $keep: 'both') {
  $keep: if(index('keys' 'values', $keep), $keep, 'both');

  @if type-of($map) == 'map' {
    $keys: ();
    $values: ();

    @each $key, $val in $map {
      $keys: append($keys, $key);
      $values: append($values, $val);
    }

    @if $keep == 'keys' {
      @return $keys;
    }
    @else if $keep == 'values' {
      @return $values;
    }
    @else {
      @return zip($keys, $values);
    }
  }

  @return if(type-of($map) != 'list', ($value,), $map);

}

/// Safely return a value from a map.
///
/// @param {Map} $map - Map to retrieve a value from.
/// @param {String} $key - Name of the map key.
///
/// @returns {List} Found value.
@function map-safe-get($map, $key) {
  @if (type-of($map) == 'map' or (type-of($map) == 'list' and length($map) == 0)) {
    @if (map-has-key($map, $key)) {
      @return map-get($map, $key);
    }
    @else {
      @error 'Key: `#{$key}` is not available in `#{$map}`';
    }
  }
  @else {
    @error '`#{$map}` is not a valid map';
  }
}