Class('DataStore.Sync', {

    methods : {

        log : function () {
            var response = // somehow get the response from logging operation

            return response
        },


        save : function () {
            this.log()

            var response = // somehow get the response from saving operation

            if (response.err) throw response.err

            return response
        }
    }
})


var store = new DataStore.Sync

try {
    var response = store.save()
} catch (e) {
    // do smth
} finally {
    // do smth
}