thenable.diff

diff --git a/lib/Mojo/IOLoop/Delay.pm b/lib/Mojo/IOLoop/Delay.pm
index b918b1fcf..27c8e03a4 100644
--- a/lib/Mojo/IOLoop/Delay.pm
+++ b/lib/Mojo/IOLoop/Delay.pm
@@ -18,12 +18,27 @@ sub data { Mojo::Util::_stash(data => @_) }

 sub pass { $_[0]->begin->(@_) }

+sub reject  { shift->_finish(error  => @_) }
+sub resolve { shift->_finish(finish => @_) }
+
 sub steps {
   my $self = shift->remaining([@_]);
   $self->ioloop->next_tick($self->begin);
   return $self;
 }

+sub then {
+  my ($self, $finish, $error) = @_;
+
+  my $next = $self->new(ioloop => $self->ioloop);
+  $self->on(finish => sub { shift; $next->resolve(@_) });
+  $self->on(error  => sub { shift; $next->reject(@_) });
+  $next->on(finish => $finish) if $finish;
+  $next->on(error  => $error)  if $error;
+
+  return $next;
+}
+
 sub wait {
   my $self = shift;
   return if $self->ioloop->is_running;
@@ -34,22 +49,27 @@ sub wait {

 sub _die { $_[0]->has_subscribers('error') ? $_[0]->ioloop->stop : die $_[1] }

+sub _finish {
+  my ($self, $event) = (shift, shift);
+  $self->{done} ? return $self : $self->{done}++;
+  return $self->remaining([])->emit($event => @_);
+}
+
 sub _step {
   my ($self, $id, $offset, $len) = (shift, shift, shift, shift);

   $self->{args}[$id]
     = [@_ ? defined $len ? splice @_, $offset, $len : splice @_, $offset : ()];
-  return $self if $self->{fail} || --$self->{pending} || $self->{lock};
+  return $self if $self->{done} || --$self->{pending} || $self->{lock};
   local $self->{lock} = 1;
   my @args = map {@$_} @{delete $self->{args}};

   $self->{counter} = 0;
   if (my $cb = shift @{$self->remaining}) {
-    eval { $self->$cb(@args); 1 }
-      or (++$self->{fail} and return $self->remaining([])->emit(error => $@));
+    eval { $self->$cb(@args); 1 } or $self->reject($@);
   }

-  return $self->remaining([])->emit(finish => @args) unless $self->{counter};
+  return $self->resolve(@args) unless $self->{counter};
   $self->ioloop->next_tick($self->begin) unless $self->{pending};
   return $self;
 }
diff --git a/t/mojo/delay.t b/t/mojo/delay.t
index 35e51d1a5..210da8ba8 100644
--- a/t/mojo/delay.t
+++ b/t/mojo/delay.t
@@ -20,6 +20,17 @@ $end2->();
 $delay->wait;
 is_deeply \@results, [1, 1], 'right results';

+# Thenable
+my ($resolve, $reject, $resolve2, $reject2);
+$delay = Mojo::IOLoop::Delay->new;
+my $delay2 = $delay->then(sub { $resolve = pop }, sub { $reject = pop });
+$delay2->then(sub { $resolve2 = pop }, sub { $reject2 = pop });
+$delay->resolve('works');
+is $resolve,  'works', 'right result';
+is $resolve2, 'works', 'right result';
+is $reject,   undef,   'no result';
+is $reject2,  undef,   'no result';
+
 # Argument splicing
 $delay = Mojo::IOLoop::Delay->new;
 Mojo::IOLoop->next_tick($delay->begin);