static/js/pager: Avoid stacking load listeners

1 files changed, 22 insertions, 17 deletions

diff --git a/assets/js/index.js b/assets/js/index.js
index 491cf59..5bbcd1a 100644
--- a/assets/js/index.js
+++ b/assets/js/index.js
@@ -13,20 +13,21 @@
     const link = function() {
         url = self.location.href.split("#")[0].split("?")[0];
     };
-    const scrollRestore = function(url) {
-        if (history.scrollRestoration) history.scrollRestoration = "manual";
-        pager = JSON.parse(localStorage[key]);
+    const scrollHash = function(url, load = false) {
         const hash = self.location.hash;
         const fragment = hash.slice(1) && document.getElementById(hash.slice(1));
-        const fragmentInURL = hash.length > 0;
-        if (fragmentInURL && document.body.contains(fragment)) {
-            pager[url] = self.pageYOffset;
-            localStorage[key] = JSON.stringify(pager);
-            fragment.scrollIntoView();
-            return self.addEventListener("DOMContentLoaded", function() {
-                fragment.scrollIntoView();
-            });
+        const fragmented = hash.length > 0;
+        const hashed = fragmented && document.body.contains(fragment);
+        if (hashed) {
+            self.location.hash = hash;
+            if (load) fragment.scrollIntoView();
         }
+        return hashed;
+    };
+    const scrollRestore = function(url) {
+        if (history.scrollRestoration) history.scrollRestoration = "manual";
+        if (scrollHash(url)) return;
+        pager = JSON.parse(localStorage[key]);
         if (pager[url] > 0) {
             clearInterval(seek);
             self.scrollTo(0, pager[url]);
@@ -60,12 +61,9 @@
             history.go(-1);
         }
     };
-    self.addEventListener("DOMContentLoaded", function() {
-        self.addEventListener("click", function(event) {
-            const up = document.getElementById("top");
-            const back = document.getElementById("back");
-            scrollReverse(back, up, event);
-        });
+    self.addEventListener("load", function() {
+        link();
+        scrollHash(url, true);
     });
     [
         "DOMContentLoaded",
@@ -77,6 +75,13 @@
             if (event.type === "pageshow") {
                 return event.persisted && self.scrollTo(0, pager[url]);
             }
+            if (event.type === "DOMContentLoaded") {
+                self.addEventListener("click", function(event) {
+                    const up = document.getElementById("top");
+                    const back = document.getElementById("back");
+                    scrollReverse(back, up, event);
+                });
+            }
             link();
             scrollRestore(url);
         });