gsioteam/EMPromise

A promise framework for Objective-C

EMPromise

A promise framework for Objective-C.

Usage

Just like JavScript Promise.

[EMPromise promise:^(promise_resolve_block  _Nonnull resolve, promise_reject_block  _Nonnull reject) {
    NSLog(@"1 %s", dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL));
    resolve([EMPromise wait:5]);
} queue:queue].then(^(id result) {
    NSLog(@"2 %s", dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL));
    return [EMPromise wait:5];
}).then(^(id result) {
    NSLog(@"3 %s", dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL));
    return [EMPromise wait:5];
}).then(^(id result) {
    NSLog(@"4 %s", dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL));
    @throw [NSException exceptionWithName:@"Test"
                                    reason:@"test"
                                  userInfo:nil];
    return [EMPromise wait:5];
}).then(^(id result) {
    NSLog(@"5 %s", dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL));
    return [EMPromise wait:5];
}).then(^id(id result) {
    NSLog(@"6 %s", dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL));
    return nil;
}).catchError(^(NSError *error) {
    NSLog(@"catch %@ %s", error, dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL));
});

Catch Exception

[EMPromise promise:^(promise_resolve_block  _Nonnull resolve, promise_reject_block  _Nonnull reject) {
    @throw [NSException exceptionWithName:@"Test"
                                    reason:@"test"
                                  userInfo:nil];
}].catchError(^(NSError *error) {
    NSLog(@"catch %@", error);
});

Timeout

[EMPromise promise:^(promise_resolve_block  _Nonnull resolve, promise_reject_block  _Nonnull reject) {
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(20 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        resolve(@(0));
    });
}].timeout(10).then(^id _Nullable(id  _Nullable result) {
    NSLog(@"result %@", result);
    return nil;
}).catchError(^(NSError *error) {
    NSLog(@"error %@", error);
});

Iterator

Iterate a array.

[EMPromise forEach:arr block:^(id  _Nonnull obj, NSUInteger idx, id  _Nonnull lastResult, promise_resolve_block  _Nonnull resolve, promise_reject_block  _Nonnull reject) {
    NSInteger sum = [lastResult integerValue] + [obj integerValue];
    NSLog(@"sum : %d", (int)sum);
    resolve(@(sum));
}].then(^id _Nullable(id  _Nullable result) {
    NSLog(@"result: %@", result);
    return nil;
});

forEach function only alloc one Promise object, the efficiency is 10x faster than the efficiency of iterating by then function.

Synchronized Task

If the task is synchronized, you can get result synchronously. That means you do not need to worry about the promise would delay the task.

__block id syncResult;
[EMPromise promise:^(promise_resolve_block  _Nonnull resolve, promise_reject_block  _Nonnull reject) {
    resolve(@"hello");
}].then(^id _Nullable(id  _Nullable result) {
    syncResult = result;
    return nil;
});
NSLog(@"%@", syncResult);

[EMPromise forEach:arr
              block:^(id  _Nonnull obj, NSUInteger idx, id  _Nonnull lastResult, promise_resolve_block  _Nonnull resolve, promise_reject_block  _Nonnull reject) {
    resolve(@([lastResult integerValue] + [obj integerValue]));
}].then(^id _Nullable(id  _Nullable result) {
    syncResult = result;
    return nil;
});
NSLog(@"%@", syncResult);