add prenav hook

quartz/components/scripts/explorer.inline.ts

@@ -193,6 +193,12 @@ async function setupExplorer(currentSlug: FullSlug) {
     }
     explorerUl.insertBefore(fragment, explorerUl.firstChild)
 
+    // restore explorer scrollTop position if it exists
+    const scrollTop = sessionStorage.getItem("explorerScrollTop")
+    if (scrollTop) {
+      explorerUl.scrollTop = parseInt(scrollTop)
+    }
+
     // Set up event handlers
     const explorerButtons = explorer.querySelectorAll(
       "button.explorer-toggle",
@@ -225,6 +231,13 @@ async function setupExplorer(currentSlug: FullSlug) {
   }
 }
 
+document.addEventListener("prenav", async (e: CustomEventMap["prenav"]) => {
+  // save explorer scrollTop position
+  const explorer = document.getElementById("explorer-ul")
+  if (!explorer) return
+  sessionStorage.setItem("explorerScrollTop", explorer.scrollTop.toString())
+})
+
 document.addEventListener("nav", async (e: CustomEventMap["nav"]) => {
   const currentSlug = e.detail.url
   const mobileExplorer = document.querySelector("#mobile-explorer")

quartz/components/scripts/spa.inline.ts

@@ -75,6 +75,10 @@ async function navigate(url: URL, isBack: boolean = false) {
 
   if (!contents) return
 
+  // notify about to nav
+  const event: CustomEventMap["prenav"] = new CustomEvent("prenav", { detail: {} })
+  document.dispatchEvent(event)
+
   // cleanup old
   cleanupFns.forEach((fn) => fn())
   cleanupFns.clear()
@@ -108,7 +112,7 @@ async function navigate(url: URL, isBack: boolean = false) {
     }
   }
 
-  // now, patch head
+  // now, patch head, re-executing scripts
   const elementsToRemove = document.head.querySelectorAll(":not([spa-preserve])")
   elementsToRemove.forEach((el) => el.remove())
   const elementsToAdd = html.head.querySelectorAll(":not([spa-preserve])")