import { readOnly } from '@ember/object/computed'; import { copy } from '@ember/object/internals'; import Service from '@ember/service'; let list = {}; export default Service.extend({ list: readOnly(function() { return copy(list, true); }), init() { list = {}; }, getIndexFor(url) { return list[url] || 1; }, setIndexFor(url, value) { list[url] = value; }, });