import { Effect } from "@effect/core/io/Effect/definition";
import { Env } from "@tsplus/stdlib/service/Env";
/**
 * Propagates the success value to the first element of a tuple, but
 * passes the effect input `R` along unmodified as the second element
 * of the tuple.
 * @tsplus getter effect/core/io/Effect onFirst
 * @tsplus location "@effect/core/io/Effect/operations/onFirst"
 */
export declare function onFirst<R, E, A>(self: Effect<R, E, A>): Effect<R, E, readonly [A, Env<R>]>;
//# sourceMappingURL=onFirst.d.ts.map