Sass add configuration objects to extend default params for mixins

extend.scss

// Configuration objects / Extend default mixin params with custom ones
// @src: https://hugogiraudel.com/2014/05/05/bringing-configuration-objects-to-sass/
// Default var for overriding
$params: () !default;

// @param {map} $obj - object with default params
// @param {map} $ext-obj - object params to extend the default
@function extend($obj, $ext-obj) {
    @return map-merge($obj, $ext-obj);
}

// Shorthand alias for map-get
// @param {string} $key - needed key in map
// @param {map} $map - given params map
@function get($key, $map: $params) {
    @return map-get($map, $key);
}

// Create a mixin with empty params map
@mixin exmaple($params: ()) {
    // extend defaults with given map in params
    $params: extend((
        fz: 4,
        color: red
    ), $params) !global;

    font-size: #{get(fz)}em;
    color: get(color);
}

.test1 {
  @include exmaple();
}
// =>
// .test1 {
//   font-size: 4em;
//   color: red;
// }

.test2 {
  @include exmaple((color: green));
}
// =>
// .test2 {
//   font-size: 4em;
//   color: green;
// }