Massive speed up of byPattern

pre-construct URLPatterns and don't construct URL for each req

README.md

@@ -131,8 +131,8 @@ Also, many handlers may also accept additional arguments beyond the first
 
 ### Argument shunting
 
-Most of the `by*` helpers will pass arguments on as is, or shunt the
-arguments along if they want to introduce their own, so for example,
+Most of the `by*` helpers will pass arguments on as is, or shunt the arguments
+along if they want to introduce their own, so for example,
 `byPattern(pattern, handler)` returns a handler with the type:
 
 ```ts

lib/by_pattern.ts

@@ -17,12 +17,13 @@ export function byPattern<A extends unknown[]>(
     ...args: A
   ) => Awaitable<Response | null>,
 ) {
-  return async (req: Request, ...args: A) => {
-    const patterns = Array.isArray(pattern) ? pattern : [pattern];
-    const url = new URL(req.url);
+  const patterns = Array.isArray(pattern)
+    ? pattern.map(asURLPattern)
+    : [asURLPattern(pattern)];
 
+  return async (req: Request, ...args: A) => {
     for (const pattern of patterns) {
-      const match = asURLPattern(pattern).exec(url);
+      const match = pattern.exec(req.url);
 
       if (match) {
         const res = await handler(req, match, ...args);