Node.js - Migrating from Swig to Nunjucks in Express

Question

I have a Node.js app. I've been building this app for a while and it currently uses Swig as the view engine. I'm setting it as the view engine using the following code:

// Use swig.    
const swig = require('swig');
app.engine('html', swig.renderFile);
if (app.get('env') === 'development') {
  swig.setDefaults({ cache: false });
}

app.set('views', path.join(__dirname, '../views'));
app.set('view engine', 'html'); 

This has been working well. However, I have some downtime so I thought now would be a good time to migrate to Nunjucks . So, I replaced the above with:

// Use nunjucks.    
const nunjucks = require('nunjucks');
app.engine('html', nunjucks.renderFile);
if (app.get('env') === 'development') {
  nunjucks.setDefaults({ cache: false });
}
app.set('views', path.join(__dirname, '../views'));
app.set('view engine', 'html');    

When I start up my site, I now get an error. The error is:

    throw new Error('callback function required');
    ^

Error: callback function required
    at EventEmitter.engine (C:\MyProject\node_modules\express\lib\application.js:294:11)
    at EventEmitter.module.exports (C:\MyProject\src\index.js:16:9)
    at EventEmitter.configure
...

What am I doing wrong? What callback is being sought after? I know I'm going to have some syntactical errors once I start using the Nunjucks engine. However, I'm just trying to figure out how to get the Nunjucks engine loaded.

Answer 1

Templating engines usually have their own method of configuration. For Nunjucks, you should use this:

const nunjucks = require('nunjucks');

nunjucks.configure('views', {
  express : app,
  noCache : app.get('env') === 'development',
  ...
});

Documentation here .