Extract the union of E (error) types across every ChildInput
in a variadic tuple, recursing into nested arrays. Primitives (string,
number, boolean, null, undefined) and Readables contribute never and
fall out of the union.
Exposed so component authors can preserve E/R inference when wrapping
a primitive with variadic children — see ElementFactory's
forwarding overload for the intended usage.
Extract the union of
E(error) types across every ChildInput in a variadic tuple, recursing into nested arrays. Primitives (string, number, boolean, null, undefined) and Readables contributeneverand fall out of the union.Exposed so component authors can preserve E/R inference when wrapping a primitive with variadic children — see ElementFactory's forwarding overload for the intended usage.