Translate an object with Rails-style nested keys into an objected with nested keys. Depends on underscore.js

nested_params_to_nested_object

function nestParams(params) {
  // Translates an object that has Rails style nested keys (key1[key2][key3]: value)
  // into a nested object
  var nested = {};
  _.each(params, function(value, key) {
    createNestedObject(nested, splitKey(key), value);
  });
  return nested;
}

function createNestedObject(base, keys, value) {
  var lastKey = _.last(keys);
  var keys = _.initial(keys);

  _.each(keys, function(key) {
    base = base[key] = base[key] || {};
  });
  base = base[lastKey] = value

  return base;
}

function splitKey(string) {
  return _.map(string.split("["), function(str) { return str.replace("]", "") });
}