nodejs / express / oboe.js & pug: Get node() events to update the dom

Question

First time working with node and template engines (yes i know, terrible place to "start" but whatever). I'm building some content from a json stream, and at the end I would like to spit this content out to a div in my html page, as follows in this (updated) expressjs snippet:

app.get('/foo', function (req, res) {

  //... get my stream called 'mystream'

  //... get ready to append content for items found in json stream
  var htmlbuf = "";

  //now process the json stream:
  oboe(mystream)
  .node('{bar}', function(aBar){
    //eventually, I'd like to actually append individual new DOM elements,
    //but for now I'll settle for just spitting out raw html:
    var buffer = '<p>Found a bar with name'+ aBar.name + '</p>';
    res.render('index', {itemsfound: htmlbuf});
    });
});

index.pug:

doctype html
html
    head
        link(type='text/css', rel='stylesheet', href='./css/main.css')
        title Hello
    body
        h1 Hello world!
        div#results.listing
            items= itemsfound

I get the error 'Error: Can't set headers after they are sent'. So I believe the issue is that the oboe.node() is firing at any time and I am not sending the response content at the right time? What is the code/framework needed to wire the oboe.node() events so that they can target or create dom elements in my pug template and send the response correctly? Thanks.

Answer 1

You'll need to do something like this:

app.get('/foo', function (req, res, next) {

  //... get my stream called 'mystream'

  //... get ready to append content for items found in json stream
  var htmlbuf = "";

  //now process the json stream:
  oboe(mystream)
  .node('{bar}', function(aBar){
    //eventually, I'd like to actually append individual new DOM elements,
    //but for now I'll settle for just spitting out raw html:
    htmlbuf += '<p>Found a bar with name' + aBar.name + '</p>';
  })
  .on('fail', function (err) {
    res.statusCode = err.statusCode
    next(err.thrown)
  })
  .on('done', function () {
    res.render('index', {itemsfound: htmlbuf});
  });
});

Answer 2

Ok, I'll try.

If you want render page with some calculated content then

// js
app.get('/foo', function (req, res) {
    res.locals.var1 = 'Res.locals.var1'; // you can define vars here too

    if (!req.xhr)
        // send as html-page
        res.render('page.jade', {bar: smth-content, title: 'Hello world'}); // without var1
    else
        // send as json on ajax-request
        res.json({bar: smth-content, title: 'Hello world'}); 
});

// .jade
doctype html
html
  head
    link(type='text/css', rel='stylesheet', href='./css/main.css')
    |     
    title #{title} 
  body
    h1 Hello world!
    |   
    #{bar} #{var1}

To mix template code you can use extends and include jade keywords. Or this trick (not recommended)

// js
app.get('/foo', function (req, res) {
    res.render('row.jade', {myblock: smth-content}, function(err, html) {
        if (err)
            return res.send(err.message);
        res.render('page.jade', {myblock: html});
    }); 
});

// page.jade
doctype html
html
  head
    link(type='text/css', rel='stylesheet', href='./css/main.css')
  body
    #{myblock} 

// myblock.jade
p Found a bar with name #{myblock}