Simple Mongo map-reduce

interactions_map_reduce.js

var mapFunction = function() {
  emit(this.facebook_object_id, 1);
};

var reduceFunction = function(key, values) {
  return Array.sum(values);
};

var options = {
  out: {inline: 1},
};

function compare(v1, v2) {
  if (v1.value < v2.value) {
    return -1;
  } else if (v1.value > v2.value) {
    return 1;
  } else {
    return 0;
  }
}

var results = db.interactions.mapReduce(mapFunction, reduceFunction, options).results;
var sorted = results.sort(compare).reverse().splice(0, 25);

db ||= Mongo::Connection.new("localhost", 27017).db("taste_profiler_production")