fix(makeStyles): handle comma separated selectors

change/@fluentui-make-styles-e8e5cc37-473f-49b4-9102-50c88f7b022e.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "fix(makeStyles): handle comma separated selectors",
+  "packageName": "@fluentui/make-styles",
+  "email": "olfedias@microsoft.com",
+  "dependentChangeType": "patch"
+}

packages/make-styles/src/runtime/compileCSS.test.ts

@@ -1,4 +1,4 @@
-import { compileCSS, CompileCSSOptions } from './compileCSS';
+import { compileCSS, CompileCSSOptions, normalizePseudoSelector } from './compileCSS';
 
 const defaultOptions: Pick<
   CompileCSSOptions,
@@ -155,3 +155,23 @@ describe('compileCSS', () => {
     });
   });
 });
+
+describe('normalizePseudoSelector', () => {
+  it('handles basic ', () => {
+    expect(normalizePseudoSelector(':hover')).toMatchInlineSnapshot(`"&:hover"`);
+  });
+
+  it('handles spacing', () => {
+    expect(normalizePseudoSelector(' :hover')).toMatchInlineSnapshot(`"& :hover"`);
+  });
+
+  it('handles multiple pseudos', () => {
+    expect(normalizePseudoSelector(':focus:hover')).toMatchInlineSnapshot(`"&:focus:hover"`);
+  });
+
+  it('handles comma separated pseudos', () => {
+    expect(normalizePseudoSelector('& :hover, & :focus')).toMatchInlineSnapshot(`"& :hover, & :focus"`);
+    expect(normalizePseudoSelector(':focus,:hover')).toMatchInlineSnapshot(`"&:focus,&:hover"`);
+    expect(normalizePseudoSelector(':focus, :hover')).toMatchInlineSnapshot(`"&:focus,& :hover"`);
+  });
+});

packages/make-styles/src/runtime/compileCSS.ts

@@ -19,10 +19,32 @@ export interface CompileCSSOptions {
   rtlValue?: number | string;
 }
 
+const PSEUDO_SELECTOR_REGEX = /,( *[^ &])/g;
+
 function repeatSelector(selector: string, times: number) {
   return new Array(times + 2).join(selector);
 }
 
+/**
+ * Normalizes pseudo selectors to always contain &, requires to work properly with comma-separated selectors.
+ *
+ * @example
+ *   ":hover" => "&:hover"
+ *   " :hover" => "& :hover"
+ *   ":hover,:focus" => "&:hover,&:focus"
+ *   " :hover, :focus" => "& :hover,& :focus"
+ */
+export function normalizePseudoSelector(pseudoSelector: string): string {
+  return (
+    '&' +
+    normalizeNestedProperty(
+      // Regex there replaces a comma, spaces and an ampersand if it's present with comma and an ampersand.
+      // This allows to normalize input, see examples in JSDoc.
+      pseudoSelector.replace(PSEUDO_SELECTOR_REGEX, ',&$1'),
+    )
+  );
+}
+
 export function compileCSSRules(cssRules: string): string[] {
   const rules: string[] = [];
 
@@ -86,10 +108,12 @@ export function compileCSS(options: CompileCSSOptions): [string /* ltr definitio
 
     cssRule = `${globalSelector} { ${ltrRule}; ${rtlRule} }`;
   } else {
-    cssRule = `${classNameSelector}${pseudo} ${cssDeclaration};`;
+    const normalizedPseudo = normalizePseudoSelector(pseudo);
+
+    cssRule = `${classNameSelector}{${normalizedPseudo} ${cssDeclaration}};`;
 
     if (rtlProperty) {
-      cssRule = `${cssRule}; ${rtlClassNameSelector}${pseudo} ${rtlCSSDeclaration};`;
+      cssRule = `${cssRule}; ${rtlClassNameSelector}${normalizedPseudo} ${rtlCSSDeclaration};`;
     }
   }