jade (for nodejs) substrings in templates - node.js

Question

Would anyone please advise how in jade for nodejs I can truncate a string to a number of characters/words, ideally conscious about the HTML markup within the string?
This should be similar to Django's truncatechars/truncatewords and truncatechars_html/truncatewords_html filters.
If this doesn't exist in jade, which way is right to go? I'm starting my first nodejs+express+CouchDB app, and could do it within nodejs code but it seems that filters are much more appropriate.
I would also consider writing a filter like this (and others) if I knew how :))
Just a quick illustration:
// in nodejs:
// body variable comes from CouchDB
res.render('home.jade', { title : "test", featuredNews : eval(body)});
// in home.jade template:
ul.thumbnails
each article in featuredNews.rows
a(href="#"+article.slug)
li.span4
div.value.thumbnail
img(align='left',src='http://example.com/image.png')
p!= article.value.description:truncatewords_html(30)
So I've made up the truncatewords_html(30) thing to illustrate what I think it should be similar to.
Will appreciate any ideas!
Thanks,
Igor

Answer 1

Here is a little "truncate_words" function:
function truncate( value, arg ) {
var value_arr = value.split( ' ' );
if( arg < value_arr.length ) {
value = value_arr.slice( 0, arg ).join( ' ' );
}
return value;
}
You can use it before sending the string to the template, or in the template using a helper method.

Answer 2

cheerio is a nice little library that does a subset of jquery and jsdom. Then it's easy:
app.helpers({
truncateWords_html : function(html, words){
return cheerio(html).text().split(/\s/).slice(0, words).join(" ")
}
})
Then, in a jade template use:
#{truncateWords_html(article.value.description, 30)}
This looks like a generic way to add any filters, hurray! :))