apply patch from https://github.com/iv-org/inv_sig_helper/issues/36#issuecomment-2529907394

src/consts.rs

@@ -20,8 +20,20 @@ pub static NSIG_FUNCTION_ENDINGS: &[&str] = &[
 
 pub static REGEX_SIGNATURE_TIMESTAMP: &Lazy<Regex> = regex!("signatureTimestamp[=:](\\d+)");
 
-pub static REGEX_SIGNATURE_FUNCTION: &Lazy<Regex> =
-    regex!("\\bc&&\\(c=([a-zA-Z0-9$]{2,})\\(decodeURIComponent\\(c\\)\\)");
+pub static REGEX_SIGNATURE_FUNCTION: Lazy<Regex> = Lazy::new(|| {
+    Regex::new(concat!(
+        r#"(?:"#,
+            // Pattern 1
+            r#"\b[a-zA-Z0-9$]+&&\([a-zA-Z0-9$]+=([a-zA-Z0-9$]{2,})\(decodeURIComponent\([a-zA-Z0-9$]+\)\)\)"#,
+            r#"|"#,
+            // Pattern 2
+            r#"([a-zA-Z0-9$]+)\s*=\s*function\(\s*[a-zA-Z0-9$]+\s*\)\s*\{\s*[^}]+?\.split\(\s*""\s*\)[^}]+?\.join\(\s*""\s*\)"#,
+            r#"|"#,
+            // Pattern 3
+            r#"(?:\b|[^a-zA-Z0-9$])([a-zA-Z0-9$]{2,})\s*=\s*function\(\s*a\s*\)\s*\{\s*a\s*=\s*a\.split\(\s*""\s*\)"#,
+        r#")"#
+    )).unwrap()
+});
 pub static REGEX_HELPER_OBJ_NAME: &Lazy<Regex> = regex!(";([A-Za-z0-9_\\$]{2,})\\...\\(");
 
 pub static NSIG_FUNCTION_NAME: &str = "decrypt_nsig";

src/player.rs

@@ -18,6 +18,12 @@ pub enum FetchUpdateStatus {
     CannotFetchPlayerJS,
     NsigRegexCompileFailed,
     PlayerAlreadyUpdated,
+    CannotMatchSignature
+}
+
+fn fixup_n_function_code(code: &str) -> String {
+    let re = regex::Regex::new(r#";\s*if\s*\(\s*typeof\s+[a-zA-Z0-9_$]+\s*===?\s*["']undefined["']\s*\)\s*return\s+[a-zA-Z0-9_$]+;"#).unwrap();
+    re.replace_all(code, ";").to_string()
 }
 
 pub async fn fetch_update(state: Arc<GlobalState>) -> Result<(), FetchUpdateStatus> {
@@ -140,18 +146,26 @@ pub async fn fetch_update(state: Arc<GlobalState>) -> Result<(), FetchUpdateStat
                 i.get(1).unwrap().as_str()
             }
         };
+        nsig_function_code = fixup_n_function_code(&nsig_function_code);
         debug!("got nsig fn code: {}", nsig_function_code);
         break;
     }
 
     // Extract signature function name
-    let sig_function_name = REGEX_SIGNATURE_FUNCTION
-        .captures(&player_javascript)
-        .unwrap()
-        .get(1)
-        .unwrap()
-        .as_str();
-
+    let sig_function_name = match REGEX_SIGNATURE_FUNCTION.captures(&player_javascript) {
+        Some(captures) => {
+            // Try groups 1, 2, and 3 which contain the signature function name
+            [1, 2, 3].iter()
+                .find_map(|&i| captures.get(i))
+                .map(|m| m.as_str())
+                .ok_or(FetchUpdateStatus::CannotMatchSignature)?
+        }
+        None => {
+            error!("Could not match signature function pattern");
+            return Err(FetchUpdateStatus::CannotMatchSignature);
+        }
+    };
+    debug!("sig function name: {}", sig_function_name);
     let mut sig_function_body_regex_str: String = String::new();
     sig_function_body_regex_str += &sig_function_name.replace("$", "\\$");
     sig_function_body_regex_str += "=function\\([a-zA-Z0-9_]+\\)\\{.+?\\}";