Express error: write after end

Question

I'm having issues with this code I'm trying to write. For some reason I get the error listed in the title. I'm pretty sure this is an issue with the async concept. How can I fix this?

pokeRouter.get('/sightings/:value([a-z]+)', function (req, res) {
var test = {};
pokemon.find().each(function(err, item) {
    if (item == null) {
        res.end();
    } else if ((req.params.value == item.type1) || (req.params.value == item.type2)) {
        sightings.find({pokedex_id: item._id}).toArray(function(err, docs) {
            if (docs == null) {
                return null;
            }
            res.write(JSON.stringify(docs));
        });
    }
});
});

Answer 1

Most likely you have an item in your find() list (not at the end) that is null . At that point you end the response ( res.end() ). However there are one or more items after that null item which are not null , causing a res.write() . This is what is causing your 'write after end' error. Make sure you only call res.end() after you have finished writing your entire response.