/// <summary> /// Chain a sequence of operations using promises. /// Takes a collection of functions each of which starts an async operation and yields a promise. /// </summary> public static IFpromise Sequence(IEnumerable <Func <IFpromise> > fns) { return(fns.Aggregate( Fpromise.Resolved(), (prevFpromise, fn) => { return prevFpromise.Then(() => fn()); } )); }
/// <summary> /// Returns a promise that resolves when all of the promises in the enumerable argument have resolved. /// Returns a promise of a collection of the resolved results. /// </summary> public static IFpromise <IEnumerable <FpromisedT> > All(IEnumerable <IFpromise <FpromisedT> > promises) { var promisesArray = promises.ToArray(); if (promisesArray.Length == 0) { return(Fpromise <IEnumerable <FpromisedT> > .Resolved(EnumerableExtensions.Empty <FpromisedT>())); } var remainingCount = promisesArray.Length; var results = new FpromisedT[remainingCount]; var resultFpromise = new Fpromise <IEnumerable <FpromisedT> >(); resultFpromise.WithName("All"); promisesArray.Each((promise, index) => { promise .Catch(ex => { if (resultFpromise.CurState == FpromiseState.Pending) { // If a promise errorred and the result promise is still pending, reject it. resultFpromise.Reject(ex); } }) .Then(result => { results[index] = result; --remainingCount; if (remainingCount <= 0) { // This will never happen if any of the promises errorred. resultFpromise.Resolve(results); } }) .Done(); }); return(resultFpromise); }