Calling a helper function with callback from a Jade template

I've just started working with Node.js so please forgive any stupidity!!! I'm trying to create a new application using Node.js. Im using the Express framework with a Postgresql database. The problem is that in my view, I wanted to to call a function. So I used a helper function that is called from my jade file. But because this function accesses the database, I tried to use callback inorder to make it work.

However, I can't seem to call a function from my jade template with the last argument as a function. The helper function worked fine when there was only one parameter being passed and it wasn't a callback function. But because the database query took a while, the the data was never displayed. But when I try to call a function with callback from my jade template, I get a syntax error.

My function call in my jade template:

#{ nameAndVersion(result.bu_entrep_id, function(error, result)) }

My helper function (It's simple because I was trying to get it to work):

exports.helpers= {
nameAndVersion: function(entid, callback) {
var x=1;
     callback(null, x);
     console.log(1);
}
};

My error:

500 SyntaxError: Unexpected token )

So, basically, I want to call a helper function from my jade template and have that function be a callback function.

You want to do :

  1. Parse template
  2. Retrieve data
  3. Render template with data

Express templating is expected to do :

  1. Retrieve data
  2. Parse and render data

You should not have to execute complexe code once you've started rendering (what if you database is unavailable ?).

Jade helpers only have a formating purpose, not functionnal.

What you should do, instead of calling an helper, is giving the necessary data when calling the renderer.

app.get('anyPage', function(req, res) {
   database.doSomeDataBaseQuery( /* Data base callback */ function(data, err) {
     if(!err) res.render('pageTemplate', {dataBaseData:data});
   }
});