Fetch until ok

etc/hotreload.js

@@ -1,8 +1,19 @@
 let build_id = "";
 
+async function fetch_until_ok(uri)
+{
+    while (true) {
+        try {
+            return await fetch(uri);
+        } catch {
+
+        }
+    }
+}
+
 async function fetch_build_id()
 {
-    const response = await fetch("/build-id");
+    const response = await fetch_until_ok("/build-id");
     const json = await response.json();
     return json.build_id;
 }