strip trailing "_" for params parsing

Author: nlynzaad

packages/router-core/src/path.ts

@@ -218,8 +218,7 @@ export const parsePathname = (
   return parsed
 }
 
-const PARAM_RE = /^\$[^_](.*[^_])?$/ // $paramName
-const PARAM_NON_NESTED_RE = /^\$.{1,}_$/ // $paramName_
+const PARAM_RE = /^\$.{1,}$/ // $paramName
 const PARAM_W_CURLY_BRACES_RE = /^(.*?)\{(\$[a-zA-Z_$][a-zA-Z0-9_$]*)\}(.*)$/ // prefix{$paramName}suffix
 const OPTIONAL_PARAM_W_CURLY_BRACES_RE =
   /^(.*?)\{-(\$[a-zA-Z_$][a-zA-Z0-9_$]*)\}(.*)$/ // prefix{-$paramName}suffix
@@ -266,8 +265,11 @@ function baseParsePathname(pathname: string): ReadonlyArray<Segment> {
 
   segments.push(
     ...split.map((part): Segment => {
+      // strip tailing underscore for non-nested paths
+      const partToMatch = part.slice(-1) === '_' ? part.slice(0, -1) : part
+
       // Check for wildcard with curly braces: prefix{$}suffix
-      const wildcardBracesMatch = part.match(WILDCARD_W_CURLY_BRACES_RE)
+      const wildcardBracesMatch = partToMatch.match(WILDCARD_W_CURLY_BRACES_RE)
       if (wildcardBracesMatch) {
         const prefix = wildcardBracesMatch[1]
         const suffix = wildcardBracesMatch[2]
@@ -280,7 +282,7 @@ function baseParsePathname(pathname: string): ReadonlyArray<Segment> {
       }
 
       // Check for optional parameter format: prefix{-$paramName}suffix
-      const optionalParamBracesMatch = part.match(
+      const optionalParamBracesMatch = partToMatch.match(
         OPTIONAL_PARAM_W_CURLY_BRACES_RE,
       )
       if (optionalParamBracesMatch) {
@@ -296,7 +298,7 @@ function baseParsePathname(pathname: string): ReadonlyArray<Segment> {
       }
 
       // Check for the new parameter format: prefix{$paramName}suffix
-      const paramBracesMatch = part.match(PARAM_W_CURLY_BRACES_RE)
+      const paramBracesMatch = partToMatch.match(PARAM_W_CURLY_BRACES_RE)
       if (paramBracesMatch) {
         const prefix = paramBracesMatch[1]
         const paramName = paramBracesMatch[2]
@@ -309,20 +311,10 @@ function baseParsePathname(pathname: string): ReadonlyArray<Segment> {
         }
       }
 
-      // Check for non-nested bare parameter format: $paramName_ (without curly braces)
-      if (PARAM_NON_NESTED_RE.test(part)) {
-        const paramName = part.slice(1, -1)
-        return {
-          type: SEGMENT_TYPE_PARAM,
-          value: '$' + paramName,
-          prefixSegment: undefined,
-          suffixSegment: undefined,
-        }
-      }
-
       // Check for bare parameter format: $paramName (without curly braces)
-      if (PARAM_RE.test(part)) {
-        const paramName = part.substring(1)
+      if (PARAM_RE.test(partToMatch)) {
+        const paramName = partToMatch.substring(1)
+
         return {
           type: SEGMENT_TYPE_PARAM,
           value: '$' + paramName,
@@ -332,7 +324,7 @@ function baseParsePathname(pathname: string): ReadonlyArray<Segment> {
       }
 
       // Check for bare wildcard: $ (without curly braces)
-      if (WILDCARD_RE.test(part)) {
+      if (WILDCARD_RE.test(partToMatch)) {
         return {
           type: SEGMENT_TYPE_WILDCARD,
           value: '$',
@@ -344,8 +336,8 @@ function baseParsePathname(pathname: string): ReadonlyArray<Segment> {
       // Handle regular pathname segment
       return {
         type: SEGMENT_TYPE_PATHNAME,
-        value: part.includes('%25')
-          ? part
+        value: partToMatch.includes('%25')
+          ? partToMatch
               .split('%25')
               .map((segment) => decodeURI(segment))
               .join('%25')