fix: drastically improve processing speed of VideoInfosWithDownloadFormatsResponse

Author: b5i

Sources/YouTubeKit/Utils/String+ytkRegexMatches.swift

@@ -42,4 +42,14 @@ public extension String {
         guard let regex = try? NSRegularExpression(pattern: stringRegex) else { return nil }
         return self.ytkFirstGroupMatch(for: regex)
     }
+    
+    /// Gets the first substring that is between a prefix and a suffix (**excluding them**)
+    func ytkFirstSubstringBetween(prefix: String, suffix: String) -> String? {
+        guard let prefixRange = self.range(of: prefix) else { return nil }
+        let afterPrefix = prefixRange.upperBound
+
+        guard let suffixRange = self[afterPrefix...].range(of: suffix) else { return nil }
+
+        return String(self[afterPrefix..<suffixRange.lowerBound])
+    }
 }

Sources/YouTubeKit/YouTubeResponseTypes/VideoInfos/VideoInfosWithDownloadFormatsResponse.swift

@@ -54,7 +54,7 @@ public struct VideoInfosWithDownloadFormatsResponse: YouTubeResponse {
 
         let (instructionArray, playerJs, playerName) = try processPlayerScrapping(playerPath: playerPath)
 
-        guard let stringJSONData = dataToString.ytkFirstGroupMatch(for: "var ytInitialPlayerResponse = ([\\S\\s]*\\}\\}\\}\\})[\\S\\s]*;</script><div id=\"player\"") else {
+        guard let stringJSONData = dataToString.ytkFirstSubstringBetween(prefix: "var ytInitialPlayerResponse = ", suffix: ";</script><div id=\"player\"") else {
             throw ResponseError(step: .decodeData, reason: "Couldn't get player's JSON data.")
         }