minor enhancements

nlynzaad · nlynzaad · commit e2cbaf96827b · 2025-10-28T03:22:20.000+02:00
diff --git a/packages/router-core/src/utils.ts b/packages/router-core/src/utils.ts
@@ -489,25 +489,25 @@ export function findLast<T>(
   return undefined
 }
 
-const DECODE_IGNORE_LIST = [
-  '%',
-  '\\',
-  '/',
-  ';',
-  ':',
-  '@',
-  '&',
-  '=',
-  '+',
-  '$',
-  ',',
-].map((c) => encodeURIComponent(c))
+const DECODE_IGNORE_LIST = new Map([
+  ['%', '%25'],
+  ['\\', '%5C'],
+  ['/', '%2F'],
+  [';', '%3B'],
+  [':', '%3A'],
+  ['@', '%40'],
+  ['&', '%26'],
+  ['=', '%3D'],
+  ['+', '%2B'],
+  ['$', '%24'],
+  [',', '%2C'],
+])
 
 export function decodePathSegment(
   part: string,
-  decodeIgnore: Array<string> = DECODE_IGNORE_LIST,
+  decodeIgnore: Array<string> = Array.from(DECODE_IGNORE_LIST.values()),
   startIndex = 0,
-) {
+): string {
   function decode(part: string) {
     try {
       return decodeURIComponent(part)
@@ -523,22 +523,36 @@ export function decodePathSegment(
     }
   }
 
-  if (part === '' || !part.match(/%../g)) return part
+  // if the path segment does not contain any encoded uri components return the path as is
+  if (part === '' || !part.match(/%[0-9A-Fa-f]{2}/g)) return part
 
+  // decode the path / path segment by splitting it into parts defined by the ignore list.
+  // once these pieces have been decoded, join them back together to form the final decoded path segment with the ignored character in place.
+  // we walk through the ignore list linearly, breaking the segment up into pieces and decoding each piece individually.
+  // use index traversal to avoid making unnecessary copies of the array.
   for (let i = startIndex; i < decodeIgnore.length; i++) {
     const char = decodeIgnore[i]
 
+    // check if the part includes the current ignore character
+    // if it doesn't continue to the next ignore character
     if (char && part.includes(char)) {
+      // split the part into pieces that needs to be checked and decoded
       const partsToDecode = part.split(char)
       const partsToJoin: Array<string> = []
 
+      // now check and decode each piece individually taking into consideration the remaining ignored characters.
+      // since we are walking through the list linearly, we only need to consider ignore items not yet traversed.
       for (const partToDecode of partsToDecode) {
+        // once we have traversed the entire ignore list, each decoded part is returned.
         partsToJoin.push(decodePathSegment(partToDecode, decodeIgnore, i + 1))
       }
 
+      // and join them back together to form the final decoded path segment with the ignored character in place.
       return partsToJoin.join(char)
     }
   }
 
+  // once we have reached the end of the ignore list, we start walking back returning each decoded part.
+  // should there be no matching characters, the path segment as a whole will be decoded.
   return decode(part)
 }
