mapSecond
import { mapSecond } from "https://github.gh-proxy.cn/raw.githubusercontent.com/baetheus/fun/main/fn_either.ts";Map over the left return value of a FnEither.
@example
import * as FE from "./fn_either.ts";
import { pipe } from "./fn.ts";
const result1 = pipe(
FE.id<number>(),
FE.mapSecond((n: number) => n + 1),
)(0); // Right(0)
const result2 = pipe(
FE.idLeft<number>(),
FE.mapSecond(n => n + 1),
)(0); // Left(1)