Indeed I need reactivity. The dataset I need for the client have to be generated from several related/linked collections.
Using methods to get dataset from multiples collection is easy and I was trying to call them using simple:reactive-methods from a reactive context like helpers.
However, I think that pub/subs are specifically designed for this purpose. My question is how can I return a dataset from publish function, which was generated from multiples collections (several queries and specific logic) but the result is not precisely a collection (not a cursor) ?