fix(styles): emit correct values for component tokens in zones (#11573)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

packages/styles/package.json

@@ -47,6 +47,7 @@
     "browserslist-config-carbon": "^11.0.0",
     "css": "^3.0.0",
     "cssnano": "^5.1.9",
+    "lodash.isequal": "^4.5.0",
     "postcss": "^8.4.14",
     "postcss-flexbugs-fixes": "^5.0.2",
     "rimraf": "^3.0.2",

packages/styles/scss/__tests__/zone-test.js

@@ -0,0 +1,76 @@
+/**
+ * Copyright IBM Corp. 2018, 2018
+ *
+ * This source code is licensed under the Apache-2.0 license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @jest-environment node
+ */
+
+'use strict';
+
+const { SassRenderer } = require('@carbon/test-utils/scss');
+const css = require('css');
+const isEqual = require('lodash.isequal');
+
+const { render } = SassRenderer.create(__dirname);
+
+describe('zone', () => {
+  it('should set a component token value to the theme of a zone', async () => {
+    const { get, result } = await render(`
+      @use '../themes';
+      @use '../components/button/tokens';
+      @use '../zone';
+
+      $_: get('themes', (
+        white: themes.$white,
+        g10: themes.$g10,
+        g90: themes.$g90,
+        g100: themes.$g100,
+      ));
+      $_: get('tokens', tokens.$button-tokens);
+    `);
+
+    const themes = Array.from(Object.entries(get('themes').value));
+    const tokensByTheme = new Map(
+      themes.map(([theme]) => {
+        return [theme, new Map()];
+      })
+    );
+
+    // Group each of the button tokens into their values by theme
+    const buttonTokens = get('tokens');
+    for (const [token, { values }] of Object.entries(buttonTokens.value)) {
+      for (const { theme, value } of values) {
+        const match = themes.find(([_id, themeMap]) => {
+          return isEqual(themeMap, theme);
+        });
+
+        tokensByTheme.get(match[0]).set(token, value);
+      }
+    }
+
+    // When including the `_zone.scss` file, we generate a stylesheet with four
+    // classes, one per theme.
+    const { stylesheet } = css.parse(result.css.toString());
+
+    for (const rule of stylesheet.rules) {
+      // For each selector, we check that every button token that we have
+      // defined for this theme is emitted in CSS with the expected value
+      const [_prefix, theme] = rule.selectors[0].split('--');
+      const tokens = tokensByTheme.get(theme);
+      const includesComponentTokens = Array.from(tokens.entries()).every(
+        ([token, value]) => {
+          return rule.declarations.find((declaration) => {
+            return (
+              declaration.property.includes(token) &&
+              declaration.value === value
+            );
+          });
+        }
+      );
+
+      expect(includesComponentTokens).toBe(true);
+    }
+  });
+});

packages/styles/scss/_zone.scss

@@ -78,9 +78,9 @@ $-components: (
           $theme-values: map.get($value, values);
 
           @each $theme-value in $theme-values {
-            $theme: map.get($theme-value, theme);
             $value: map.get($theme-value, value);
-            @if theme.matches($theme, theme.$theme) and
+
+            @if theme.matches(map.get($theme-value, theme), $theme) and
               meta.type-of($value) ==
               color
             {

yarn.lock

@@ -2227,6 +2227,7 @@ __metadata:
     browserslist-config-carbon: ^11.0.0
     css: ^3.0.0
     cssnano: ^5.1.9
+    lodash.isequal: ^4.5.0
     postcss: ^8.4.14
     postcss-flexbugs-fixes: ^5.0.2
     rimraf: ^3.0.2