Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.14)
// Compass (v1.0.3)
// ----

$config: (
  margin: 20px,
  padding: 10px 0,
  color: red
);

.original {
  @each $k, $v in $config {
    #{$k}: $v;
  }
}

$config: map-merge($config, (margin: 25px));

.after-one-merge {
  @each $k, $v in $config {
    #{$k}: $v;
  }
}

$config: map-merge($config, (margin: 10px 30px, font: sans-serif));

.after-two-merges {
  @each $k, $v in $config {
    #{$k}: $v;
  }
}

SassMeister-output.css

.original {
  margin: 20px;
  padding: 10px 0;
  color: red; }

.after-one-merge {
  margin: 25px;
  padding: 10px 0;
  color: red; }

.after-two-merges {
  margin: 10px 30px;
  padding: 10px 0;
  color: red;
  font: sans-serif; }