Splits an array of objects into groups

organize-by.js

/**
 * Expects data to be an array of objects.
 * The key will be one of the keys in the objects.
 */
function organizeBy(key, data) {
  var results = {};
  data.forEach(function(obj) {
    var value = obj[key];
    if (!results[value]) {
      results[value] = [];
    }
    results[value].push(obj);
  })
  return results;
}