Passing an array to a JSON object for Jade rendering


Question

I have a node.js server written in express and at a certain moment I send to some .jade page an array. The problem is that when rendering the Jade page, the Jade compiler renders the array as [object Object] and the JavaScript compiler on Chrome complains about it saying "Unexpected identifier".

This is the Jade code:

!!! 5
html(lang="en")
    head
    title= "Rankings"

    body
        h1 Ranking

        div(id="rankings")

    script(type='text/javascript')

        function fillRanking(){
            var rankArray = #{ranking};
            alert("inside fillranking");
            var divElement = document.getElementById("rankings");
            for(var i = 0; i< rankArray.length; i++){
                divElements.innerHTML += "" + i+1 + ". " + rankArray[i].Username + " " + rankArray[i].Points;
            }
        }

        fillRanking();

As you can see it's really simple, I just fill a div with the info given by what's inside the #{ranking} variable passed by node.js to Jade. The alert on the second line doesn't fire because the Unexpected Identifier error happens as soon as I try to assign the #{ranking} variable.

The following is the code in my node.js with express

app.get('/ranking', function (req, res) {
    //get the first ten people in the ranking
    var firstTen = getRanking(10, function(results){
        //compute the array of results
        var result = {
            ranking: [],
        }
        for(var i = 0; i < results.length; i++){
            result.ranking[i] = results[i];
        }
        //render the ranking with all the info
        console.log(result);
        res.render(__dirname + '/pages/ranking/ranking.jade', {
            ranking: result,
        });
    });
});

I create an object with inside an array of results, I put the results I found out of the query inside it and I pass it to the rendering engine. The console.log(results) call prints the result object correctly, for example like this:

{ ranking: 
   [ { Username: 'usr1',
       _id: 4ed27319c1d767f70e000002,
       Points: 100 },
     { Username: 'usr2',
       _id: 4ed27326c1d767f70e000003,
       Points: 100 } ] 
}

I don't really know how to handle the variable passed to the Jade page. Whichever thing I do I keep getting the "Unexpected identifier" error. Does anyone of you know how do I solve this?

Thanks

1
15
11/28/2011 8:44:49 AM

Accepted Answer

Looking at the comments above and investigating a little bit more, here's what I've found to work:

Use this on your javascript (/controller):

...
res.render(__dirname + '/pages/ranking/ranking.jade', {
    ranking: JSON.stringify(ranking),
})
...

And on jade template:

...
function fillRanking(){
  var rankArray = !{ranking};
  alert("inside fillranking");
...

This works because !{} doesn't perform escaping.

31
1/18/2012 11:31:03 AM

This works for me.

JSON.stringify the array (or any arbitrary JSON object really) on the server and then JSON.parse it on the client.

server-side:

res.render(__dirname + '/pages/ranking/ranking.jade', {
    ranking: JSON.stringify(result),
});

client-side:

var rankArray = JSON.parse( !{JSON.stringify(ranking)} );

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