preferable error handler location for promise style codes in nodejs

preferable_error_hander_location.js

/**
 * always put errorHandler in the last 'then' with a 'null' logic handler, 
 * so that all errors will be caught 
 */
someModule.promiseFunc()
    .then(function (data) {
        //TODO other logic
    })
    .then(null, errorHandler);