MongoDB lists - get every Nth item

Question

I have a Mongodb schema that looks roughly like:

[
  {
    \"name\" : \"name1\",
    \"instances\" : [ 
      {
        \"value\" : 1,
        \"date\" : ISODate         


        

Answer 1

Or with just a find block:

db.Collection.find({}).then(function(data) {
  var ret = [];
  for (var i = 0, len = data.length; i < len; i++) {
    if (i % 3 === 0 ) {
      ret.push(data[i]);
    }
  }
  return ret;
});

Returns a promise whose then() you can invoke to fetch the Nth modulo'ed data.