Enable using method for server errors (#23)

Author: zefir-git

src/Server.ts

@@ -52,7 +52,7 @@ class Server {
         }
         catch (e) {
             if (e instanceof Request.BadUrlError) {
-                this.errors._get(ServerErrorRegistry.ErrorCodes.BAD_URL)._send(res, this);
+                this.errors._get(ServerErrorRegistry.ErrorCodes.BAD_URL, null)._send(res, this);
                 return;
             }
             if (e instanceof Request.SocketClosedError)
@@ -74,10 +74,10 @@ class Server {
         }
         catch (e) {
             if (e instanceof RouteRegistry.NoRouteError)
-                response = this.errors._get(ServerErrorRegistry.ErrorCodes.NO_ROUTE);
+                response = this.errors._get(ServerErrorRegistry.ErrorCodes.NO_ROUTE, apiRequest);
             else {
                 console.error("Internal Server Error:", e);
-                response = this.errors._get(ServerErrorRegistry.ErrorCodes.INTERNAL);
+                response = this.errors._get(ServerErrorRegistry.ErrorCodes.INTERNAL, apiRequest);
             }
         }
         response._send(res, this, apiRequest);

src/ServerErrorRegistry.ts

@@ -1,11 +1,12 @@
 import {Response} from "./response/Response.js";
+import {Request} from "./Request.js";
 import {TextResponse} from "./response/TextResponse.js";
 
 /**
  * A registry for server errors.
  */
 class ServerErrorRegistry {
-    private readonly responses: Record<ServerErrorRegistry.ErrorCodes, Response>;
+    private readonly responses: Record<ServerErrorRegistry.ErrorCodes, Response | ((req?: Request) => Response)>;
 
     /**
      * Create a new server error registry initialised with default responses.
@@ -28,13 +29,15 @@ class ServerErrorRegistry {
      * @param code The server error code.
      * @param response The response to send.
      */
-    public register(code: ServerErrorRegistry.ErrorCodes, response: Response) {
+    public register(code: ServerErrorRegistry.ErrorCodes, response: Response | ((req?: Request) => Response)) {
         this.responses[code] = response;
     }
 
     /** @internal */
-    public _get(code: ServerErrorRegistry.ErrorCodes): Response {
-        return this.responses[code];
+    public _get(code: ServerErrorRegistry.ErrorCodes, req: Request | null): Response {
+        const r = this.responses[code];
+        if (typeof r === "function") return r(req ?? void 0);
+        return r;
     }
 }