diff --git a/static/js/browser_history.js b/static/js/browser_history.js
index 654c80825a..db67011267 100644
--- a/static/js/browser_history.js
+++ b/static/js/browser_history.js
@@ -30,6 +30,15 @@ export function set_hash_before_overlay(hash) {
     state.hash_before_overlay = hash;
 }
 
+export function update_web_public_hash(hash) {
+    // Returns true if hash is web public compatible.
+    if (hash_util.is_spectator_compatible(hash)) {
+        state.spectator_old_hash = hash;
+        return true;
+    }
+    return false;
+}
+
 export function save_old_hash() {
     state.old_hash = window.location.hash;
 
diff --git a/static/js/hashchange.js b/static/js/hashchange.js
index 0d3c41e03b..35567adafd 100644
--- a/static/js/hashchange.js
+++ b/static/js/hashchange.js
@@ -315,14 +315,9 @@ function do_hashchange_overlay(old_hash) {
 function hashchanged(from_reload, e) {
     const current_hash = window.location.hash;
     const old_hash = e && (e.oldURL ? new URL(e.oldURL).hash : browser_history.old_hash());
+    const is_hash_web_public_compatible = browser_history.update_web_public_hash(current_hash);
 
     const was_internal_change = browser_history.save_old_hash();
-
-    const is_hash_web_public_compatible = hash_util.is_spectator_compatible(current_hash);
-    if (is_hash_web_public_compatible) {
-        browser_history.state.spectator_old_hash = current_hash;
-    }
-
     if (was_internal_change) {
         return undefined;
     }