Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.9)
// Compass (v1.0.1)
// ----

@function map-change-key-case($map, $case: 'lower-case') {
  $values: 'lower-case', 'upper-case';
  
  @if index($values, $case) == null {
    @error "Argument `$case` for `map-change-key-case` must be one of: #{$values}.";
  }
  
  @each $key, $value in $map {
    $new-key: call('to-' + $case, $key);
    
    @if $key != $new-key {
      $map: map-merge(map-remove($map, $key), (
        $new-key: $value
      ));
    }
  }
  
  @return $map;
}

test {
  $map: (
    'a': 1,
    'B': 2,
    'C': 3,
    'd': 4,
    'eF': 5
  );
  
  inspect: map-keys($map);
  inspect: map-keys(map-change-key-case($map));
  inspect: map-keys(map-change-key-case($map, 'upper-case'));
}

SassMeister-output.css

test {
  inspect: "a", "B", "C", "d", "eF";
  inspect: "a", "d", "b", "c", "ef";
  inspect: "B", "C", "A", "D", "EF";
}