Method FlatMap

observable_operator.go:1112–1151

FlatMap transforms the items emitted by an Observable into Observables, then flatten the emissions from those into a single Observable.

(apply ItemToObservable, opts ...Option)

// FlatMap transforms the items emitted by an Observable into Observables, then flatten the emissions from those into a single Observable.
func (o *ObservableImpl) FlatMap(apply ItemToObservable, opts ...Option) Observable {
	f := func(ctx context.Context, next chan Item, option Option, opts ...Option) {
		defer close(next)
		observe := o.Observe(opts...)
		for {
			select {
			case <-ctx.Done():
				return
			case item, ok := <-observe:
				if !ok {
					return
				}
				observe2 := apply(item).Observe(opts...)
			loop2:
				for {
					select {
					case <-ctx.Done():
						return
					case item, ok := <-observe2:
						if !ok {
							break loop2
						}
						if item.Error() {
							item.SendContext(ctx, next)
							if option.getErrorStrategy() == StopOnError {
								return
							}
						} else {
							if !item.SendContext(ctx, next) {
								return
							}
						}
					}
				}
			}
		}
	}

	return customObservableOperator(o.parent, f, opts...)
}

// ForEach subscribes to the Observable and receives notifications for each element.
func (o *ObservableImpl) ForEach(nextFunc NextFunc, errFunc ErrFunc, completedFunc CompletedFunc, opts ...Option) Disposed {