import { Effect } from "@effect/core/io/Effect/definition";
/**
 * 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 fluent ets/Effect onFirst
 * @tsplus location "@effect/core/io/Effect/operations/onFirst"
 */
export declare function onFirst<R, E, A>(self: Effect<R, E, A>, __tsplusTrace?: string): import("../definition").Effect<R, E, import("@tsplus/stdlib/data/Tuple").Tuple<[A, import("@tsplus/stdlib/service/Env").Env<R>]>>;
//# sourceMappingURL=onFirst.d.ts.map