Sass function map-get-next

gistfile1.sass

/// Function to get next map item
/// returns next map item or fallback value if map, key or next item does not exist
///
/// @author Simon Koch
///
/// @access public
///
/// @param {Map} $map - Sass list map
/// @param {String} $key - List map key
/// @param {String} $fallback (false) - Fallback value if map, key or next item does not exist
///
/// @example scss - Usage
/// $map: (
/// 	a: 100px,
/// 	b: 200px
/// );
///
/// .foo {
/// 	width: map-get-next($map, a);
/// }
///
/// .bar {
///		width: map-get-next($map, b, auto);
/// }
///
/// @example css - CSS output
/// .foo {
/// 	width: 200px;
/// }
///
/// .bar {
/// 	width: auto;
/// }

@function map-get-next($map, $key, $fallback: false) {

	// Check if map is valid
	@if type_of($map) == map {

		// Check if key exists in map
		@if map_has_key($map, $key) {

			// Init index counter variable
			$i: 0;

			// Init key index
			$key-index: false;

			// Traverse map for key
			@each $map-key, $map-value in $map {
				// Update index
				$i: $i + 1;

				// If map key found, set key index
				@if $map-key == $key {
					$key-index: $i;
				}

				// If next index return next value
				@if $i == $key-index + 1 {
					@return $map-value;
				}

				// If last entry return false
				@if $i == length($map) {
					@return $fallback;
				}
			}

			@warn 'No next map item for key #{$key}';
			@return $fallback;
		}

		@warn 'No valid key #{$key} in map';
		@return $fallback;
	}

	@warn 'No valid map';
	@return $fallback;
}