Generated by SassMeister.com.

input.scss

@function map-diff($map1, $map2) {
    $map1-keys: map.keys($map1);
    
    @each $key in $map1-keys {
        $map2: map.remove($map2, $key);
    }
    
    @return $map2;
}

$theme-colors: (
  "primary": "",
  "secondary": "",
  "success": "",
  "info": "",
  "warning": "",
  "danger": "",
  "light": "",
  "dark": ""
);

$expected-theme-colors: (
  "primary": "",
  "secondary": "",
  "success": "",
  "info": "",
  "warning": "",
  "danger": "",
  "light": "",
  "dark": "",
  "custom": ""
);

@debug map-diff($theme-colors, $expected-theme-colors);

output.css

@map-diff ($theme-colors, $expected-theme-colors);

settings.json

{
  "sass": {
    "compiler": "dart-sass/1.32.12",
    "extensions": {},
    "syntax": "SCSS",
    "outputStyle": "expanded"
  },
  "autoprefixer": false
}