$colors: ( primary: #BE0062, secondary: #D3A108 ); $custom: ( myBlue: #20B7CE ); $merge: map-merge($colors, $custom); @debug map-has-key($merge, "primary"); // true @debug map-has-key($merge, "secondary"); // true @debug map-has-key($merge, "myBlue"); // true @debug map-has-key($merge, "myRed"); // false