Meteor: publish 2 different projections of array elements

Question

I have elements like this one in a collection:

{
    array: [{ a:10, b: {...} }, { a:30, b: {...} }, { a:50 b: {...} }]
}

In one publicatio

Answer 1

I examined different approaches. The problem can be solved on a case-by-case basis by carefully picking fields and minding subscription order, but these solutions are flimsy and rely on non-documented arbitrary conditions.

The only real, generic solution is a virtual collection. The simplest case is simply publishing a cursor under a different, client-side collection name. For example:

function publishVirtual(sub, name, cursor) {
  var observer = cursor.observeChanges({
    added  : function(id, fields) { sub.added(name, id, fields) },
    changed: function(id, fields) { sub.changed(name, id, fields) },
    removed: function(id)         { sub.remove(name, id) }
  })

  sub.onStop(function() {
    observer.stop() // important. Otherwise, it keeps running forever
  })
}

And then, in your publication, instead of returning a cursor:

var cursor = Users.find()
publishVirtual(this, 'virtualUsers', cursor)
this.ready()