docs: put back router.options.ts

docs/app/router.options.ts

@@ -1,38 +1,48 @@
 import type { RouterConfig } from '@nuxt/schema'
-// https://router.vuejs.org/api/interfaces/routeroptions.html
-export default <RouterConfig> {
-  scrollBehavior (to, _form, savedPosition) {
-    if (history.state.stop) { return }
 
-    if (history.state.smooth) {
-      return {
-        el: history.state.smooth,
-        behavior: 'smooth'
-      }
-    }
+function findHashPosition (hash): { el: any, behavior: ScrollBehavior, top: number } {
+  const el = document.querySelector(hash)
+  // vue-router does not incorporate scroll-margin-top on its own.
+  if (el) {
+    const top = parseFloat(getComputedStyle(el).scrollMarginTop)
 
-    if (to.hash) {
-      const el = document.querySelector(to.hash) as any
-
-      if (!el) { return }
-
-      const { marginTop } = getComputedStyle(el)
-
-      const marginTopValue = parseInt(marginTop)
-
-      const offset = (document.querySelector(to.hash) as any).offsetTop - marginTopValue
-
-      return {
-        top: offset,
-        behavior: 'smooth'
-      }
-    }
-
-    // Scroll to top of window
-    if (savedPosition) {
-      return savedPosition
-    } else {
-      return { top: 0 }
+    return {
+      el: hash,
+      behavior: 'smooth',
+      top
     }
   }
 }
+
+// https://router.vuejs.org/api/#routeroptions
+export default <RouterConfig>{
+  scrollBehavior (to, from, savedPosition) {
+    const nuxtApp = useNuxtApp()
+
+    // If history back
+    if (savedPosition) {
+      // Handle Suspense resolution
+      return new Promise((resolve) => {
+        nuxtApp.hooks.hookOnce('page:finish', () => {
+          setTimeout(() => resolve(savedPosition), 50)
+        })
+      })
+    }
+
+    // Scroll to heading on click
+    if (to.hash) {
+      return new Promise((resolve) => {
+        if (to.path === from.path) {
+          setTimeout(() => resolve(findHashPosition(to.hash)), 50)
+        } else {
+          nuxtApp.hooks.hookOnce('page:finish', () => {
+            setTimeout(() => resolve(findHashPosition(to.hash)), 50)
+          })
+        }
+      })
+    }
+
+    // Scroll to top of window
+    return { top: 0 }
+  }
+}