How to create Sass feature flags

[1] _rkv-map-merge.scss

@function rkv-map-merge($maps...) {
  $collection: ();

  @each $map in $maps {
    $collection: map-merge($collection, $map);
  }

  @return $collection;
}

[2] _features.scss

// ====================
// Default placeholder.
// ====================

/*
  This is empty by default, but the intent
  is that it would be overwritten by another
  variable for a custom site implementation.
*/

// prettier-ignore
$-rkv-custom-feature-map: (
  // Leave this blank!
) !default;

// ===============================
// Features. Private to this file.
// ===============================

// prettier-ignore
$-rkv-default-feature-map: (
  charts: true,
  extras: true,
  gravity-forms: true,
  grid: true,
  storybook: true,
  syntax: true,
  wordpress: true,
) !default;

// ===================
// Merge feature maps.
// ===================

// prettier-ignore
$-rkv-merged-feature-map: rkv-map-merge(
  $-rkv-default-feature-map,
  $-rkv-custom-feature-map
) !default;

[3] _rkv-feature-flag.scss

@mixin rkv-feature-flag($flag: '') {
  @if map-get($-rkv-merged-feature-map, $flag) == true {
    @content;
  }
}

[4] _overrides.scss

@include rkv-feature-flag($flag: gravity-forms) {
  @import './gravity-forms';
}

@include rkv-feature-flag($flag: storybook) {
  @import './storybook';
}

@include rkv-feature-flag($flag: wordpress) {
  @import './wordpress';
}