I am not sure if this is intentional, but having a javascript comment that contains a single string start-end char(', ", `) will cause the rendering to fail:
let x = `<p>RazorExpress test</p>
<script>
// don't
<\/script>`
let rendered = raz.render(template);
Response: "Error: '<script>' tag at line 2 pos 18 is missing matching end tag."
For comparison this would work with EJS.