Angularjs Search service

search.service.js

(function () {

    angular
        .module('projectName')
        .service('searchService', _searchService);

    function _searchService($log, $q, _, lunr, reportsService, userService) {

        var state;
        var reindexPromise = $q.when("");
        var idFieldName = 'ms_id';
        // todo: for tests
        window.search = state = {
            index: null,
            clustersHash: {}
        };

        var service = this;

        service.reindex = _.debounce(_reindex, 300);
        service.ensureIndex = _ensureIndex;
        service.search = _search;

        // private functions
        function _ensureIndex() {
            if (state.index) return reindexPromise;

            return _reindex();
        }


        function _reindex() {
            $log.debug('Search: Clusters indexing... ');


            reindexPromise = reindexPromise.then(_fillIndex);
            return reindexPromise;
        }

        function _initializeLunr() {
            var instance = this;

            // initialize lunr-languages ru plugin
            instance.use(lunr.ru);

            // setting a field to the list of fields that will be searchable within documents in the index.
            instance.field('title', {boost: 10});

            // the property used to uniquely identify documents added to the index,
            // by default this property is 'id'
            instance.ref(idFieldName);
            
            // removed stemmer
            instance.pipeline.remove(lunr.ru.stemmer);
            instance.pipeline.remove(lunr.ru.stopWordFilter);
            instance.pipeline.add(trimmerEnRu);
            
        }
        
        function trimmerEnRu(token) {
            var result = token
                .replace(/^[^\wа-яёА-ЯЁ]+/, '')
                .replace(/[^\wа-яёА-ЯЁ]+$/, '');

            return result === '' ? undefined : result;
        };

        function _fillIndex() {


            return userService.getProfile()
                .then(function(profile) {
                    var promises = _(profile.topics).map('tag').map(_getClusters).value();
                    return $q.all(promises);
                }).then(function(results) {
                    return _.union.apply(null, results);
                }).then(function(clusters) {

                    var newIndex = lunr(_initializeLunr);
                    state.clustersHash = _.indexBy(clusters, idFieldName);
                    _.each(clusters, _.partialRight(newIndex.add.bind(newIndex), true));

                    state.index = newIndex;

                    $log.debug('Search: Clusters was indexed.');
                });
        }

        function _getClusters(id) {
            return reportsService.getReport(id).then(function(report) {
                if (!report) return [];

                _.each(report.clusters, function (cluster) { cluster.type = 'cluster'; cluster[idFieldName] = "c_" + cluster.id; });
                _.each(report.news, function (newsItem) { newsItem.type = 'news'; newsItem[idFieldName] = 'n_' + newsItem.id; });

                return report.clusters.concat(report.news);
            });
        }

        function _search(query) {
            if (!query) return [];

            var found = state.index.search(query);

            return _(found).map('ref').map(_.propertyOf(state.clustersHash)).value();
        }
    }

})();