How to make a pug template render inside of Webtask.io Node/Express serverless app?

I'm trying to render a very simple Pug template from a route in my Webtask.io serverless Node app. Here's my attempt:

'use latest';
import express from 'express';
import pug from 'pug'

const app = express();    
app.set('view engine', 'pug');
...

  app.get('/', (req, res) =>
  {
    var page = `
    #message
        h1 Hello World Foo
        h2 pug's in the house`;

    const HTML = pug.render(page);

    res.status(200).send(HTML)
  });

...
module.exports = fromExpress(app);

and here's the error I'm receiving:

Error: Pug:2:1
    1|
  > 2|     #message
-------^
    3|         h1 Hello World Foo
    4|         h2 pug's in the house

unexpected token "indent"

I've registered Pug as the view engine for the express app, however, it seems like Pug is not getting invoked. What am I missing? How do you register Pug so it will render templates inside a Webtask.io Node app?

I've not been able to find any examples doing this with Pug, however, I've found a post saying it's possible. This post talks about Webtask compiler. I cannot find how you make Pug a compiler.

I'm not married to Pug. Is there a better choice for rendering dynamic HTML from templates that will work with Webtask approach? I've Googled for Handlebars and could not find an example.

Thanks for your time.

Pug works on a two-space indentation standard. That's definitely a pug-formatted error you're seeing so that's hooked up properly.

Try this template instead:

#message
  h1 Hello World Foo
  h2 pug's in the house