fix(theme): misaligned outline indicator\

fixes #3449

Author: brc-dd

src/client/app/router.ts

@@ -1,9 +1,9 @@
-import { reactive, inject, markRaw, nextTick, readonly } from 'vue'
 import type { Component, InjectionKey } from 'vue'
+import { inject, markRaw, nextTick, reactive, readonly } from 'vue'
+import type { Awaitable, PageData, PageDataPayload } from '../shared'
 import { notFoundPageData, treatAsHtml } from '../shared'
-import type { PageData, PageDataPayload, Awaitable } from '../shared'
-import { inBrowser, withBase } from './utils'
 import { siteDataRef } from './data'
+import { getScrollOffset, inBrowser, withBase } from './utils'
 
 export interface Route {
   path: string
@@ -261,34 +261,14 @@ export function scrollTo(el: Element, hash: string, smooth = false) {
   }
 
   if (target) {
-    let scrollOffset = siteDataRef.value.scrollOffset
-    let offset = 0
-    let padding = 24
-    if (typeof scrollOffset === 'object' && 'padding' in scrollOffset) {
-      padding = scrollOffset.padding
-      scrollOffset = scrollOffset.selector
-    }
-    if (typeof scrollOffset === 'number') {
-      offset = scrollOffset
-    } else if (typeof scrollOffset === 'string') {
-      offset = tryOffsetSelector(scrollOffset, padding)
-    } else if (Array.isArray(scrollOffset)) {
-      for (const selector of scrollOffset) {
-        const res = tryOffsetSelector(selector, padding)
-        if (res) {
-          offset = res
-          break
-        }
-      }
-    }
     const targetPadding = parseInt(
       window.getComputedStyle(target).paddingTop,
       10
     )
     const targetTop =
       window.scrollY +
       target.getBoundingClientRect().top -
-      offset +
+      getScrollOffset() +
       targetPadding
     function scrollToTarget() {
       // only smooth scroll if distance is smaller than screen height.
@@ -300,14 +280,6 @@ export function scrollTo(el: Element, hash: string, smooth = false) {
   }
 }
 
-function tryOffsetSelector(selector: string, padding: number): number {
-  const el = document.querySelector(selector)
-  if (!el) return 0
-  const bot = el.getBoundingClientRect().bottom
-  if (bot < 0) return 0
-  return bot + padding
-}
-
 function handleHMR(route: Route): void {
   // update route.data on HMR updates of active page
   if (import.meta.hot) {

src/client/app/utils.ts

@@ -107,3 +107,36 @@ export function defineClientComponent(
     }
   }
 }
+
+export function getScrollOffset() {
+  let scrollOffset = siteDataRef.value.scrollOffset
+  let offset = 0
+  let padding = 24
+  if (typeof scrollOffset === 'object' && 'padding' in scrollOffset) {
+    padding = scrollOffset.padding
+    scrollOffset = scrollOffset.selector
+  }
+  if (typeof scrollOffset === 'number') {
+    offset = scrollOffset
+  } else if (typeof scrollOffset === 'string') {
+    offset = tryOffsetSelector(scrollOffset, padding)
+  } else if (Array.isArray(scrollOffset)) {
+    for (const selector of scrollOffset) {
+      const res = tryOffsetSelector(selector, padding)
+      if (res) {
+        offset = res
+        break
+      }
+    }
+  }
+
+  return offset
+}
+
+function tryOffsetSelector(selector: string, padding: number): number {
+  const el = document.querySelector(selector)
+  if (!el) return 0
+  const bot = el.getBoundingClientRect().bottom
+  if (bot < 0) return 0
+  return bot + padding
+}

src/client/theme-default/composables/outline.ts

@@ -1,8 +1,9 @@
 import type { DefaultTheme } from 'vitepress/theme'
 import { onMounted, onUnmounted, onUpdated, type Ref } from 'vue'
+import { getScrollOffset } from '../../app/utils'
 import type { Header } from '../../shared'
-import { useAside } from './aside'
 import { throttleAndDebounce } from '../support/utils'
+import { useAside } from './aside'
 
 // cached list of anchor elements from resolveHeaders
 const resolvedHeaders: { element: HTMLHeadElement; link: string }[] = []
@@ -179,7 +180,7 @@ export function useActiveAnchor(
     // find the last header above the top of viewport
     let activeLink: string | null = null
     for (const { link, top } of headers) {
-      if (top > scrollY + offsetDocTop) {
+      if (top > scrollY + offsetDocTop + getScrollOffset()) {
         break
       }
       activeLink = link