From 9f519bc930b134f66a84c2109dd0ff1626a7dc72 Mon Sep 17 00:00:00 2001
From: Javi Velasco <javier.velasco86@gmail.com>
Date: Thu, 28 Apr 2022 18:03:47 +0200
Subject: [PATCH] Extract `absolutePagePath` util

---
 packages/next/server/dev/next-dev-server.ts | 21 +++++++++----------
 packages/next/server/page-path-utils.ts     | 23 ++++++++++++++++++++-
 2 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/packages/next/server/dev/next-dev-server.ts b/packages/next/server/dev/next-dev-server.ts
index 975cdc6fb8add..61462cf9dd98c 100644
--- a/packages/next/server/dev/next-dev-server.ts
+++ b/packages/next/server/dev/next-dev-server.ts
@@ -40,7 +40,7 @@ import {
   isDynamicRoute,
 } from '../../shared/lib/router/utils'
 import Server, { WrappedBuildError } from '../next-server'
-import { normalizePagePath } from '../page-path-utils'
+import { absolutePathToPage, normalizePagePath } from '../page-path-utils'
 import Router from '../router'
 import { getPathMatch } from '../../shared/lib/router/utils/path-match'
 import { hasBasePath, replaceBasePath } from '../router-utils'
@@ -242,10 +242,8 @@ export default class DevServer extends Server {
 
     let resolved = false
     return new Promise((resolve, reject) => {
-      const pagesDir = this.pagesDir
-
       // Watchpack doesn't emit an event for an empty directory
-      fs.readdir(pagesDir!, (_, files) => {
+      fs.readdir(this.pagesDir, (_, files) => {
         if (files?.length) {
           return
         }
@@ -257,7 +255,7 @@ export default class DevServer extends Server {
       })
 
       let wp = (this.webpackWatcher = new Watchpack())
-      wp.watch([], [pagesDir!], 0)
+      wp.watch([], [this.pagesDir], 0)
 
       wp.on('aggregated', async () => {
         const routedMiddleware = []
@@ -270,20 +268,21 @@ export default class DevServer extends Server {
             continue
           }
 
+          const pageName = absolutePathToPage(
+            this.pagesDir,
+            fileName,
+            this.nextConfig.pageExtensions
+          )
+
           if (regexMiddleware.test(fileName)) {
             routedMiddleware.push(
-              `/${relative(pagesDir!, fileName).replace(/\\+/g, '/')}`
+              `/${relative(this.pagesDir, fileName).replace(/\\+/g, '/')}`
                 .replace(/^\/+/g, '/')
                 .replace(regexMiddleware, '/')
             )
             continue
           }
 
-          let pageName =
-            '/' + relative(pagesDir!, fileName).replace(/\\+/g, '/')
-          pageName = pageName.replace(regexPageExtension, '')
-          pageName = pageName.replace(/\/index$/, '') || '/'
-
           invalidatePageRuntimeCache(fileName, safeTime)
           const pageRuntimeConfig = await getPageRuntime(
             fileName,
diff --git a/packages/next/server/page-path-utils.ts b/packages/next/server/page-path-utils.ts
index 27d93f8605e9b..e41a3476faf3d 100644
--- a/packages/next/server/page-path-utils.ts
+++ b/packages/next/server/page-path-utils.ts
@@ -1,5 +1,5 @@
 import { isDynamicRoute } from '../shared/lib/router/utils'
-import { join, posix } from '../shared/lib/isomorphic/path'
+import { join, posix, relative } from '../shared/lib/isomorphic/path'
 import { flatten } from '../shared/lib/flatten'
 
 /**
@@ -100,3 +100,24 @@ export function getPagePaths(normalizedPagePath: string, extensions: string[]) {
     })
   )
 }
+
+/**
+ * Given the absolute path to the pages folder, an absolute file path for a
+ * page and the page extensions, this function will return the page path
+ * relative to the pages folder. It doesn't consider index tail. Example:
+ *  - `/Users/rick/my-project/pages/foo/bar/baz.js` -> `/foo/bar/baz`
+ *
+ * @param pagesDir Absolute path to the pages folder.
+ * @param filepath Absolute path to the page.
+ * @param extensions Extensions allowed for the page.
+ */
+export function absolutePathToPage(
+  pagesDir: string,
+  pagePath: string,
+  extensions: string[]
+) {
+  return removePagePathTail(
+    normalizePathSep(ensureLeadingSlash(relative(pagesDir, pagePath))),
+    extensions
+  )
+}