Add utility for tag combination & negation

src/index.test.ts

@@ -1,4 +1,4 @@
-import { toId, storyNameFromExport, isExportStory } from './index.js';
+import { toId, storyNameFromExport, isExportStory, combineTags } from './index.js';
 
 describe('toId', () => {
   const testCases: [string, string, string | undefined, string][] = [
@@ -93,3 +93,21 @@ describe('isExportStory', () => {
     expect(isExportStory('a', { includeStories: /a/, excludeStories: /b/ })).toBeTruthy();
   });
 });
+
+describe('combineTags', () => {
+  it.each([
+    [[], []],
+    [
+      ['a', 'b'],
+      ['a', 'b'],
+    ],
+    [
+      ['a', 'b', 'b'],
+      ['a', 'b'],
+    ],
+    [['a', 'b', '!b'], ['a']],
+    [['b', '!b', 'b'], ['b']],
+  ])('combineTags(%o) -> %o', (tags, expected) => {
+    expect(combineTags(...tags)).toEqual(expected);
+  });
+});

src/index.ts

@@ -83,5 +83,20 @@ export const parseKind = (kind: string, { rootSeparator, groupSeparator }: Separ
   };
 };
 
+/**
+ * Combine a set of project / meta / story tags, removing duplicates and handling negations.
+ */
+export const combineTags = (...tags: string[]): string[] => {
+  const result = tags.reduce((acc, tag) => {
+    if (tag.startsWith('!')) {
+      acc.delete(tag.slice(1));
+    } else {
+      acc.add(tag);
+    }
+    return acc;
+  }, new Set<string>());
+  return Array.from(result);
+};
+
 export { includeConditionalArg } from './includeConditionalArg';
 export * from './story';

src/story.ts

@@ -349,6 +349,11 @@ export type BaseAnnotations<TRenderer extends Renderer = Renderer, TArgs = Args>
    * Define a custom render function for the story(ies). If not passed, a default render function by the renderer will be used.
    */
   render?: ArgsStoryFn<TRenderer, TArgs>;
+
+  /**
+   * Named tags for a story, used to filter stories in different contexts.
+   */
+  tags?: Tag[];
 };
 
 export type ProjectAnnotations<
@@ -457,11 +462,6 @@ export interface ComponentAnnotations<TRenderer extends Renderer = Renderer, TAr
    * Function that is executed after the story is rendered.
    */
   play?: PlayFunction<TRenderer, TArgs>;
-
-  /**
-   * Named tags for a story, used to filter stories in different contexts.
-   */
-  tags?: Tag[];
 }
 
 export type StoryAnnotations<
@@ -484,11 +484,6 @@ export type StoryAnnotations<
    */
   play?: PlayFunction<TRenderer, TArgs>;
 
-  /**
-   * Named tags for a story, used to filter stories in different contexts.
-   */
-  tags?: Tag[];
-
   /** @deprecated */
   story?: Omit<StoryAnnotations<TRenderer, TArgs>, 'story'>;
   // eslint-disable-next-line @typescript-eslint/ban-types