Key not working?

gistfile1.txt

module.exports.getConversationPosts = exports.getConversationPosts = function getConversationPosts (conversation, cb) {
  return db.query(function (doc) {
    if (doc.conversation && doc.type && doc.type === 'note') {
      emit(doc.conversation)
    }
  }, {include_docs: true, key: conversation.id}).then(function (response) {
    // TODO This shouldn't be needed, the query should be doing this for us.
    // Actually, this isn't working at all. The conversation.id is undefined. 
    console.log('conversation', response, conversation.id)
    return _.filter(justTheDocs(response), function (doc) {
      return doc.conversation === conversation.id
    })
  }).catch(function (err) {
    return err
  })
}