How to use the @angular/language-service/src/language_service.createLanguageService function in @angular/language-service

source: 'ng'
            };
            return result;
        }
        function tryOperation(attempting, callback) {
            try {
                return callback();
            }
            catch (e) {
                info.project.projectService.logger.info("Failed to " + attempting + ": " + e.toString());
                info.project.projectService.logger.info("Stack trace: " + e.stack);
                return null;
            }
        }
        var serviceHost = new typescript_host_1.TypeScriptServiceHost(info.languageServiceHost, info.languageService);
        var ls = language_service_1.createLanguageService(serviceHost);
        serviceHost.setSite(ls);
        projectHostMap.set(info.project, serviceHost);
        proxy.getCompletionsAtPosition = function (fileName, position, options) {
            var base = oldLS.getCompletionsAtPosition(fileName, position, options) || {
                isGlobalCompletion: false,
                isMemberCompletion: false,
                isNewIdentifierLocation: false,
                entries: []
            };
            tryOperation('get completions', function () {
                var e_1, _a;
                var results = ls.getCompletionsAt(fileName, position);
                if (results && results.length) {
                    if (base === undefined) {
                        base = {
                            isGlobalCompletion: false,

function createLanguageServiceFromTypescript(host, service) {
        var ngHost = new TypeScriptServiceHost(host, service);
        var ngServer = language_service_1.createLanguageService(ngHost);
        ngHost.setSite(ngServer);
        return ngServer;
    }
    exports.createLanguageServiceFromTypescript = createLanguageServiceFromTypescript;