Using the new error's helper methods inside our current API endpoint and with our httprouter Handlers NotFound and MethodNotAllowed (will override the default responses with our helper's methods)

cmd/api/routes.go

@@ -9,6 +9,12 @@ func (app *application) routes() http.Handler {
 	// Initialize a new httprouter router instance
 	router := httprouter.New()
 
+	// Convert the notFoundResponse() helper to a http.Handler using the http.HandlerFunc() adapter, and then set it as the custom error handler for 404 Not Found responses.
+	router.NotFound = http.HandlerFunc(app.notFoundResponse)
+
+	// Likewise, convert the methodNotAllowedResponse() helper to a http.Handler and set it as the custom error handler for 405 Method Not Allowed responses
+	router.MethodNotAllowed = http.HandlerFunc(app.methodNotAllowedResponse)
+
 	/*
 		Register the relevant methods, URL patterns and handler functions for our
 		endpoints using the HandlerFunc() method. Note that http.MethodGet and