addon/helpers/storage.js
function _buildKey(context, key) {
  let appConfig = getOwner(context).resolveRegistration('config:environment');
  let addonConfig = appConfig && appConfig['ember-local-storage'] || {};
  let namespace = _getNamespace(appConfig, addonConfig);
  let delimiter = addonConfig.keyDelimiter || ':';

  return namespace ? `${namespace}${delimiter}${key}` : key;
}
function _buildKey(context, key) {
  let appConfig = getOwner(context).resolveRegistration('config:environment');
  let addonConfig = appConfig && appConfig['ember-local-storage'] || {};
  let namespace = _getNamespace(appConfig, addonConfig);
  let delimiter = addonConfig.keyDelimiter || ':';

  return namespace ? `${namespace}${delimiter}${key}` : key;
}
TODO: Add migration helper