Generated by SassMeister.com.

input.scss

$icons: (
    --1: --a,
    --2: --b,
    --3: --c
);

.colors {
    @each $name, $glyph in $icons {
        #{$name}: #{$glyph};
    }
}

output.css

.colors {
  --1: --a;
  --2: --b;
  --3: --c;
}

settings.json

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