From 9576701d8532b9697df62c96d7c8676afd985b2d Mon Sep 17 00:00:00 2001
From: Andrew G. Dunn <andrew@dunn.dev>
Date: Mon, 02 Mar 2026 16:31:53 +0000
Subject: [PATCH] fix: await micromorph() to prevent race condition with nav event handlers (#2323)

---
 quartz/components/scripts/spa.inline.ts |  217 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 214 insertions(+), 3 deletions(-)

diff --git a/quartz/components/scripts/spa.inline.ts b/quartz/components/scripts/spa.inline.ts
index 4020c23..465e793 100644
--- a/quartz/components/scripts/spa.inline.ts
+++ b/quartz/components/scripts/spa.inline.ts
@@ -1,3 +1,214 @@
-import flamethrower from 'flamethrower-router'
-const router = flamethrower()
-export default "SpaScript"
+import micromorph from "micromorph"
+import { FullSlug, RelativeURL, getFullSlug, normalizeRelativeURLs } from "../../util/path"
+import { fetchCanonical } from "./util"
+
+// adapted from `micromorph`
+// https://github.com/natemoo-re/micromorph
+const NODE_TYPE_ELEMENT = 1
+let announcer = document.createElement("route-announcer")
+const isElement = (target: EventTarget | null): target is Element =>
+  (target as Node)?.nodeType === NODE_TYPE_ELEMENT
+const isLocalUrl = (href: string) => {
+  try {
+    const url = new URL(href)
+    if (window.location.origin === url.origin) {
+      return true
+    }
+  } catch (e) {}
+  return false
+}
+
+const isSamePage = (url: URL): boolean => {
+  const sameOrigin = url.origin === window.location.origin
+  const samePath = url.pathname === window.location.pathname
+  return sameOrigin && samePath
+}
+
+const getOpts = ({ target }: Event): { url: URL; scroll?: boolean } | undefined => {
+  if (!isElement(target)) return
+  if (target.attributes.getNamedItem("target")?.value === "_blank") return
+  const a = target.closest("a")
+  if (!a) return
+  if ("routerIgnore" in a.dataset) return
+  const { href } = a
+  if (!isLocalUrl(href)) return
+  return { url: new URL(href), scroll: "routerNoscroll" in a.dataset ? false : undefined }
+}
+
+function notifyNav(url: FullSlug) {
+  const event: CustomEventMap["nav"] = new CustomEvent("nav", { detail: { url } })
+  document.dispatchEvent(event)
+}
+
+const cleanupFns: Set<(...args: any[]) => void> = new Set()
+window.addCleanup = (fn) => cleanupFns.add(fn)
+
+function startLoading() {
+  const loadingBar = document.createElement("div")
+  loadingBar.className = "navigation-progress"
+  loadingBar.style.width = "0"
+  if (!document.body.contains(loadingBar)) {
+    document.body.appendChild(loadingBar)
+  }
+
+  setTimeout(() => {
+    loadingBar.style.width = "80%"
+  }, 100)
+}
+
+let isNavigating = false
+let p: DOMParser
+async function _navigate(url: URL, isBack: boolean = false) {
+  isNavigating = true
+  startLoading()
+  p = p || new DOMParser()
+  const contents = await fetchCanonical(url)
+    .then((res) => {
+      const contentType = res.headers.get("content-type")
+      if (contentType?.startsWith("text/html")) {
+        return res.text()
+      } else {
+        window.location.assign(url)
+      }
+    })
+    .catch(() => {
+      window.location.assign(url)
+    })
+
+  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()
+
+  const html = p.parseFromString(contents, "text/html")
+  normalizeRelativeURLs(html, url)
+
+  let title = html.querySelector("title")?.textContent
+  if (title) {
+    document.title = title
+  } else {
+    const h1 = document.querySelector("h1")
+    title = h1?.innerText ?? h1?.textContent ?? url.pathname
+  }
+  if (announcer.textContent !== title) {
+    announcer.textContent = title
+  }
+  announcer.dataset.persist = ""
+  html.body.appendChild(announcer)
+
+  // morph body
+  await micromorph(document.body, html.body)
+
+  // scroll into place and add history
+  if (!isBack) {
+    if (url.hash) {
+      const el = document.getElementById(decodeURIComponent(url.hash.substring(1)))
+      el?.scrollIntoView()
+    } else {
+      window.scrollTo({ top: 0 })
+    }
+  }
+
+  // now, patch head, re-executing scripts
+  const elementsToRemove = document.head.querySelectorAll(":not([data-persist])")
+  elementsToRemove.forEach((el) => el.remove())
+  const elementsToAdd = html.head.querySelectorAll(":not([data-persist])")
+  elementsToAdd.forEach((el) => document.head.appendChild(el))
+
+  // delay setting the url until now
+  // at this point everything is loaded so changing the url should resolve to the correct addresses
+  if (!isBack) {
+    history.pushState({}, "", url)
+  }
+
+  notifyNav(getFullSlug(window))
+  delete announcer.dataset.persist
+}
+
+async function navigate(url: URL, isBack: boolean = false) {
+  if (isNavigating) return
+  isNavigating = true
+  try {
+    await _navigate(url, isBack)
+  } catch (e) {
+    console.error(e)
+    window.location.assign(url)
+  } finally {
+    isNavigating = false
+  }
+}
+
+window.spaNavigate = navigate
+
+function createRouter() {
+  if (typeof window !== "undefined") {
+    window.addEventListener("click", async (event) => {
+      const { url } = getOpts(event) ?? {}
+      // dont hijack behaviour, just let browser act normally
+      if (!url || event.ctrlKey || event.metaKey) return
+      event.preventDefault()
+
+      if (isSamePage(url) && url.hash) {
+        const el = document.getElementById(decodeURIComponent(url.hash.substring(1)))
+        el?.scrollIntoView()
+        history.pushState({}, "", url)
+        return
+      }
+
+      navigate(url, false)
+    })
+
+    window.addEventListener("popstate", (event) => {
+      const { url } = getOpts(event) ?? {}
+      if (window.location.hash && window.location.pathname === url?.pathname) return
+      navigate(new URL(window.location.toString()), true)
+      return
+    })
+  }
+
+  return new (class Router {
+    go(pathname: RelativeURL) {
+      const url = new URL(pathname, window.location.toString())
+      return navigate(url, false)
+    }
+
+    back() {
+      return window.history.back()
+    }
+
+    forward() {
+      return window.history.forward()
+    }
+  })()
+}
+
+createRouter()
+notifyNav(getFullSlug(window))
+
+if (!customElements.get("route-announcer")) {
+  const attrs = {
+    "aria-live": "assertive",
+    "aria-atomic": "true",
+    style:
+      "position: absolute; left: 0; top: 0; clip: rect(0 0 0 0); clip-path: inset(50%); overflow: hidden; white-space: nowrap; width: 1px; height: 1px",
+  }
+
+  customElements.define(
+    "route-announcer",
+    class RouteAnnouncer extends HTMLElement {
+      constructor() {
+        super()
+      }
+      connectedCallback() {
+        for (const [key, value] of Object.entries(attrs)) {
+          this.setAttribute(key, value)
+        }
+      }
+    },
+  )
+}

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