safe decoding of url encoded strings

Author: zilinskyte

Sprint-2/implement/querystring.js

@@ -5,17 +5,24 @@ function parseQueryString(queryString) {
   }
   const keyValuePairs = queryString.split("&"); // Split by '&' to get individual key-value pairs
 
+  function safeDecode(str) {
+    try {
+      return decodeURIComponent(str);
+    } catch {
+      return str; // Return original string if decoding fails
+    }
+    }
   for (const pair of keyValuePairs) {
     // Iterate over each key-value pair
     if (!pair.includes("=")) {
       // Handle missing equals sign
-      queryParams[pair] = undefined; // Assign undefined for keys without equals sign
+      queryParams[safeDecode(pair)] = undefined; // Assign undefined for keys without equals sign
       continue; // Move to the next pair
     }
-    const [key, ...rest] = pair.split("="); // array destructured into key and rest of array.
+    const [rawKey, ...rest] = pair.split("="); // array destructured into key and rest of array.
     // Split by '=' to separate key and value.
     const value = rest.join("="); // Join back any '=' in the value using rest operator
-    queryParams[key] = value; // Assign key-value pair to the result object
+    queryParams[safeDecode(rawKey)] = safeDecode(value); // Assign key-value pair to the result object
   }
 
   return queryParams;