chain method
Callback2Arg<T1, T2>
chain(
- covariant Callback2Arg<
T1, T2> ? a, - covariant Callback2Arg<
T1, T2> ? b
override
Returns a strongly-typed chained callback that calls through to the two provided callbacks, a
and b
, in order.
Useful for executing multiple callbacks where only a single callback is accepted.
Returns false
if one or more of the provided callbacks returns false
.
Gracefully handles when a
and/or b
are null, always returning a callable function.
Implementation
@override
Callback2Arg<T1, T2> chain(Callback2Arg<T1, T2>? a, Callback2Arg<T1, T2>? b) {
if (a == null) return b ?? noop;
if (b == null) return a;
dynamic chained(T1 arg1, T2 arg2) {
var aDidReturnFalse = a(arg1, arg2) == false;
var bDidReturnFalse = b(arg1, arg2) == false;
if (aDidReturnFalse || bDidReturnFalse) return false;
}
return chained;
}