Add basic HTML parsing

web/main.ts

@@ -0,0 +1,38 @@
+class VisitAnalytics {
+    observer;
+
+    constructor() {
+        window.plausible = window.plausible || function () { (window.plausible.q = window.plausible.q || []).push(arguments); };
+        if (document.readyState == "interactive")
+            this.init()
+        else
+            document.addEventListener("DOMContentLoaded", () => this.init(), false);
+    }
+
+    init() {
+        let options = {
+            root: null,
+            rootMargin: "0px",
+            threshold: 1.0
+        };
+
+        this.observer = new IntersectionObserver((entries, observer) => this.handleIntersect(entries, observer), options);
+
+        var all = document.querySelectorAll(".chapter-announce");
+        all.forEach(elem => this.observer.observe(elem));
+        this.observer.observe(document.querySelector("footer"));
+        console.log("Intersection observer ready");
+    }
+
+    handleIntersect(entries: IntersectionObserverEntry[], observer: IntersectionObserver) {
+        entries.filter(e => e.isIntersecting).forEach(e => {
+                if (e.target.className == "chapter-announce" && !e.target.nextElementSibling.querySelector("img").complete)
+                    return;
+                window.plausible("landmark", {props: {id: e.target.id ? e.target.id : e.target.tagName}});
+                observer.unobserve(e.target);
+                console.log("Reached landmark " + e.target.id ? e.target.id : e.target.tagName);
+            }
+        );
+    }
+}
+new VisitAnalytics();