import { Source , IterableActivity } from "./activity" ; function concatGen < T = any > ( concatSource ) { return function * ( source ) { yield * source ; yield * concatSource ; } ; } export function concat < T = any > ( concatSource ) ; export function concat < T > ( source , concatSource ) ; export function concat < T = any > ( s_or_n , concatSource ? ) { return concatSource !== undefined ? concatGen < T > ( concatSource ! ) ( s_or_n ) : concatGen < T > ( s_or_n ) ; }