From 9f4d420b1f5f120d8f29b7b2a74f12b390f71a36 Mon Sep 17 00:00:00 2001
From: pooya parsa <pyapar@gmail.com>
Date: Fri, 14 Aug 2020 23:42:04 +0200
Subject: [PATCH] fix(vue-app): fix regression with `scrollToTop` (#7920)

---
 .../vue-app/template/router.scrollBehavior.js | 26 ++++++++++---------
 test/dev/unicode-base.size-limit.test.js      |  2 +-
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/packages/vue-app/template/router.scrollBehavior.js b/packages/vue-app/template/router.scrollBehavior.js
index 2d124c1257..0a9eee54e4 100644
--- a/packages/vue-app/template/router.scrollBehavior.js
+++ b/packages/vue-app/template/router.scrollBehavior.js
@@ -22,21 +22,19 @@ if (process.client) {
   }
 }
 
-export default function (to, from, savedPosition) {
-  // if the returned position is falsy or an empty object,
-  // will retain current scroll position.
+  export default function (to, from, savedPosition) {
+  // If the returned position is falsy or an empty object, will retain current scroll position
   let position = false
 
-  // if no children detected and scrollToTop is not explicitly disabled
   const Pages = getMatchedComponents(to)
+
+  // Scroll to the top of the page if...
   if (
-    Pages.length < 2 &&
-    Pages.every(Page => Page.options.scrollToTop !== false)
+      // One of the children set `scrollToTop`
+      Pages.some(Page => Page.options.scrollToTop) ||
+      // scrollToTop set in only page without children
+      (Pages.length < 2 && Pages.every(Page => Page.options.scrollToTop !== false))
   ) {
-    // scroll to the top of the page
-    position = { x: 0, y: 0 }
-  } else if (Pages.some(Page => Page.options.scrollToTop)) {
-    // if one of the children has scrollToTop option set to true
     position = { x: 0, y: 0 }
   }
 
@@ -47,8 +45,12 @@ export default function (to, from, savedPosition) {
 
   const nuxt = window.<%= globals.nuxt %>
 
-  // triggerScroll is only fired when a new component is loaded
-  if (to.path === from.path && to.hash !== from.hash) {
+  if (
+    // Route hash changes
+    (to.path === from.path && to.hash !== from.hash) ||
+    // Initial load (vuejs/vue-router#3199)
+    to === from
+  ) {
     nuxt.$nextTick(() => nuxt.$emit('triggerScroll'))
   }
 
diff --git a/test/dev/unicode-base.size-limit.test.js b/test/dev/unicode-base.size-limit.test.js
index 6f22f4c9cf..3dd5fbe91c 100644
--- a/test/dev/unicode-base.size-limit.test.js
+++ b/test/dev/unicode-base.size-limit.test.js
@@ -20,7 +20,7 @@ describe('nuxt minimal vue-app bundle size limit', () => {
   it('should stay within the size limit range', async () => {
     const filter = filename => filename === 'vue-app.nuxt.js'
     const legacyResourcesSize = await getResourcesSize(distDir, 'client', { filter })
-    const LEGACY_JS_RESOURCES_KB_SIZE = 16.5
+    const LEGACY_JS_RESOURCES_KB_SIZE = 16.6
     expect(legacyResourcesSize.uncompressed).toBeWithinSize(LEGACY_JS_RESOURCES_KB_SIZE)
   })
 })