fix: support api routes at index of folder (#2101)

* feat: support finding source file when index of folder

* chore: add tests

* fix: fix prettier error

* Update test/helpers/files.spec.ts

Co-authored-by: Michal Piechowiak <misiek.piechowiak@gmail.com>

---------

Co-authored-by: Michal Piechowiak <misiek.piechowiak@gmail.com>

Author: RohitRajendran

packages/runtime/src/helpers/files.ts

@@ -353,6 +353,11 @@ export const getSourceFileForPage = (page: string, roots: string[], pageExtensio
       if (existsSync(file)) {
         return file
       }
+
+      const fileAtFolderIndex = join(root, page, `index.${extension}`)
+      if (existsSync(fileAtFolderIndex)) {
+        return fileAtFolderIndex
+      }
     }
   }
   console.log('Could not find source file for page', page)

test/fixtures/page-extensions/index/pages/api/index/index.js

@@ -0,0 +1 @@
+// noop

test/helpers/files.spec.ts

@@ -237,4 +237,13 @@ describe('getSourceFileForPage', () => {
 
     expect(filePath.replace(TEST_DIR, '')).toBe('/fixtures/page-extensions/custom/pages/api/custom.api.js')
   })
+
+  it('handles getting file when index of folder', () => {
+    const pagesDir = resolve(__dirname, '../fixtures/page-extensions/index/pages')
+    const apiRoute = '/api/index'
+
+    const filePath = getSourceFileForPage(apiRoute, [pagesDir])
+
+    expect(filePath.replace(TEST_DIR, '')).toBe('/fixtures/page-extensions/index/pages/api/index/index.js')
+  })
 })