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.\"
.IX Title "GraphQL::AsyncIterator 3pm"
.TH GraphQL::AsyncIterator 3pm "2022-03-27" "perl v5.34.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
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.nh
.SH "NAME"
GraphQL::AsyncIterator \- iterator objects that return promise to next result
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 7
\&  use GraphQL::AsyncIterator;
\&  my $i = GraphQL::AsyncIterator\->new(
\&    promise_code => $pc,
\&  );
\&  # also works when publish happens before next_p called
\&  my $promised_value = $i\->next_p;
\&  $i\->publish(\*(Aqhi\*(Aq); # now $promised_value will be fulfilled
\&
\&  $i\->close_tap; # now next_p will return undef
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Encapsulates the asynchronous event-handling needed for the
publish/subscribe behaviour needed by GraphQL::Subscription.
.SH "ATTRIBUTES"
.IX Header "ATTRIBUTES"
.SS "promise_code"
.IX Subsection "promise_code"
A hash-ref matching \*(L"PromiseCode\*(R" in GraphQL::Type::Library, which must
provide the \f(CW\*(C`new\*(C'\fR key.
.SH "METHODS"
.IX Header "METHODS"
.SS "publish(@values)"
.IX Subsection "publish(@values)"
Resolves the relevant promise with \f(CW@values\fR.
.SS "error(@values)"
.IX Subsection "error(@values)"
Rejects the relevant promise with \f(CW@values\fR.
.SS "next_p"
.IX Subsection "next_p"
Returns either a \*(L"Promise\*(R" in GraphQL::Type::Library of the next value,
or \f(CW\*(C`undef\*(C'\fR when closed off. Do not call this if a previous promised next
value has not been settled, as a queue is not maintained.
.PP
The promise will have each of the sets of handlers added by \*(L"map_then\*(R"
appended.
.SS "close_tap"
.IX Subsection "close_tap"
Switch to being closed off. \*(L"next_p\*(R" will return \f(CW\*(C`undef\*(C'\fR as soon as
it runs out of \*(L"publish\*(R"ed values. \*(L"publish\*(R" will throw an exception.
\&\fB\s-1NB\s0\fR This will not cause the settling of any outstanding promise returned
by \*(L"next_p\*(R".
.ie n .SS "map_then($then, $catch)"
.el .SS "map_then($then, \f(CW$catch\fP)"
.IX Subsection "map_then($then, $catch)"
Adds the handlers to this object's list of handlers, which will be
attached to promises returned by \*(L"next_p\*(R". Returns self.