universal JavaScript app, an url param and a variadic route combined is very useful to display custom 404 error page.</p>
<p>In a case of 404 Not Found error, the server send back the custom page to client. When Mithril is loaded, it will redirect client to the default route because it can&#39;t know that route.</p>
<pre><code class="language-javascript">m.route(document.body, &quot;/&quot;, {
  &quot;/&quot;: homeComponent,
  // [...]
  &quot;/:404...&quot;: errorPageComponent
});</code></pre>
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