AngularJS\Typescript - Synchronously execute promises

synchronous.ts

private synchronouslyExecuteCommands = (commands: Array<IProductModificationCommand>, product: Model.Product): ng.IPromise<any> => {
    var commandPromises = this.$q.when();
    _.each(commands, (command: IProductModificationCommand) => {
            commandPromises = commandPromises.then(() => {
                    return command.execute(product);
            });
    });
    return commandPromises;
}