Strip index.stories.js from autotitle

MIGRATION.md

@@ -1,7 +1,7 @@
 <h1>Migration</h1>
 
 - [From version 6.4.x to 6.5.0](#from-version-64x-to-650)
-  - [CSF3 auto-title duplicate filename](#csf3-auto-title-duplicate-filename)
+  - [CSF3 auto-title redundant filename](#csf3-auto-title-redundant-filename)
 - [From version 6.3.x to 6.4.0](#from-version-63x-to-640)
   - [Automigrate](#automigrate)
   - [CRA5 upgrade](#cra5-upgrade)
@@ -192,13 +192,13 @@
 
 ## From version 6.4.x to 6.5.0
 
-### CSF3 auto-title duplicate filename
+### CSF3 auto-title redundant filename
 
 SB 6.4 introduced experimental "auto-title", in which a story's location in the sidebar (aka `title`) can be automatically inferred from its location on disk. For example, the file `atoms/Button.stories.js` might result in the title `Atoms/Button`.
 
-The heuristic failed in the common scenario in which each component gets its own directory, e.g. `atoms/Button/Button.stories.js`, which would result in the redundant `atoms/Button/Button`.
+The heuristic failed in the common scenario in which each component gets its own directory, e.g. `atoms/Button/Button.stories.js`, which would result in the redundant title `Atoms/Button/Button`. Alternatively, `atoms/Button/index.stories.js` would result in `Atoms/Button/Index`.
 
-To address this problem, 6.5 introduces a new heuristic to removes the filename if it matches the directory name (case insensitive). So `atoms/Button/Button.stories.js` would result in `atoms/Button`.
+To address this problem, 6.5 introduces a new heuristic to removes the filename if it matches the directory name (case insensitive) or `index`. So `atoms/Button/Button.stories.js` and `atoms/Button/index.stories.js` would both result in the title `Atoms/Button`.
 
 Since CSF3 is experimental, we are introducing this technically breaking change in a minor release. If you desire the old structure, you can manually specify the title in file. For example:
 

lib/store/src/autoTitle.test.ts

@@ -49,6 +49,15 @@ describe('autoTitle', () => {
       ).toMatchInlineSnapshot(`To/Button`);
     });
 
+    it('match with trailing index', () => {
+      expect(
+        auto(
+          './path/to/button/index.stories.js',
+          normalizeStoriesEntry({ directory: './path' }, options)
+        )
+      ).toMatchInlineSnapshot(`To/Button`);
+    });
+
     it('match with hyphen path', () => {
       expect(
         auto(

lib/store/src/autoTitle.ts

@@ -23,11 +23,11 @@ const stripExtension = (path: string[]) => {
   return parts;
 };
 
-// deal with files like "atoms/button/button.stories.js"
-const removeTrailingDuplicate = (paths: string[]) => {
+// deal with files like "atoms/button/{button,index}.stories.js"
+const removeRedundantFilename = (paths: string[]) => {
   let prevVal: string;
   return paths.filter((val, index) => {
-    if (index === paths.length - 1 && val === prevVal) {
+    if (index === paths.length - 1 && (val === prevVal || val === 'Index')) {
       return false;
     }
     prevVal = val;
@@ -58,7 +58,7 @@ export const autoTitleFromSpecifier = (fileName: string, entry: NormalizedStorie
     const titleAndSuffix = slash(pathJoin([titlePrefix, suffix]));
     let path = titleAndSuffix.split('/');
     path = stripExtension(path).map(startCase);
-    path = removeTrailingDuplicate(path);
+    path = removeRedundantFilename(path);
     return path.join('/');
   }
   return undefined;