Using Iron Router to waitOn subscription that's dependent on data from a doc that will come from another subscription

Question

I'm having trouble configuring the waitOn portion of a route where one of the subscription's parameters is determined by the value from a doc that comes from a different subscription.

The collections in play are Candidates and Interviews. An interview will have one and only one candidate. Here's some sample data:

candidate = {
    _id: 1
    firstName: 'Some',
    lastName: 'Developer'
    //other props
};

interview = { 
    _id: 1,
    candidateId: 1
    //other props
};

The route is configured as follows.

this.route('conductInterview', {
    path: '/interviews/:_id/conduct', //:_id is the interviewId
    waitOn: function () {
        return [
            Meteor.subscribe('allUsers'),
            Meteor.subscribe('singleInterview', this.params._id),
            // don't know the candidateId to lookup because it's stored
            // in the interview doc
            Meteor.subscribe('singleCandidate', ???), 
            Meteor.subscribe('questions'),
            Meteor.subscribe('allUsers')
        ];
    },
    data: function () {
        var interview = Interviews.findOne(this.params._id);
        return {
            interview: interview,
            candidate: Candidates.findOne(interview.candidateId);
        };
    }
});

The problem is that I don't have a candidateId to pass to the singleCandidate subscription in the waitOn method because it's stored in the interview doc.

I've thought of two possible solutions, but I don't really like either of them. The first is to change the route to something like /interviews/:_id/:candidateId/conduct. The second is to denormalize the data and store the candidate's info in the interview doc.

Are there any other options to accomplish this besides those two?

Answer 1

You can change your publish function singleCandidate to take interviewId as paramater instead of candidateId and pass this.params._id