# QPromise::fail

Since: 0.1.0

QPromise<T>::fail(Function onRejected) -> QPromise<T>

Shorthand to promise.then(nullptr, onRejected) for handling errors in promise chains, similar to the native C++ catch statement (opens new window):

promise.fail([](const MyException& error) {
    // {...}
}).fail([](const QException& error) {
    // {...}
}).fail([](const std::exception& error) {
    // {...}
}).fail([]() {
    // {...} catch-all
});