Meteor app level Mongo `Distinct` emulation

gistfile1.js

  var userTeams = Teams.find({
    members: {
      $in: [this.userId]
    }
  });
  
  var userTeamMembers = _.chain(userTeams.fetch())
    .map(function (team) {
      return team.members;
    })
    .flatten()
    .uniq()
    .value();