PHP - 如何显示自定义错误和停止流程

i have a mini route and mvc system

I have some Classes and methods to centralize some functions inside the app for ex.

Router::route('login')

This method will create a url for the alias matched inside the class Router, the problem comes when the alias doesn't exists, i have this validation

public static function route(string $name) {
    $base = self::$_instance->getBasePath();
    $alias = self::$_instance->getAliases();

    $method = self::$_instance->_request->server('requestMethod');

    if( isset($alias[$name]) && $alias[$name][$method] ) {
        $route = $alias[$name];
        return $base . $route[$method]['uri'];
    }
    return ("Route {$name} not defined.");
}

So when the route does not exist return Route about not defined, but when I see the browser nothing is shown on screen.

View Code

<nav class="navbar navbar-expand-md navbar-light bg-light fixed-top" style="box-shadow: 0px 0px 2px #ccc;background: #fdfdfd!important;">
    <ul class="navbar-nav mr-auto">
        <a class="nav-link" href="<?= Router::route('home') ?>">Home</a>
        <a class="nav-link" href="<?= Router::route('site.about') ?>">About</a>
        <a class="nav-link" href="<?= Router::route('site.contact') ?>">Contact</a>
    </ul>
    <ul class="navbar-nav ml-auto">
        <?php if(Router::has('auth.login')) { ?>
            <?php if(Capsule::app()->user()->isAuth()) { ?>
                    <a class="nav-link" href="/home">Home</a>
                <?php } else { ?>
                    <a class="nav-link" href="<?= Router::route('auth.login') ?>">Login</a>
                    <a class="nav-link" href="<?= Router::route('auth.register') ?>">Register</a>
                <?php } ?>
        <?php } ?>
    </ul>
</nav>

I Only have the routes: Login, Register and Home, the Contact and About doesnt exists

in the browser i have the links to /Route not defined when i hover the mouse in Contact or About link

but i want that the project flow stop and throw a error like Laravel or Yii Exceptions Something like

Route About not defined

On the whole screen.

Thanks in advance.