First attempt at zio inspiried monad in TypeScript

zio.ts

import { Either, left, right } from "fp-ts/lib/Either";
import { Task, task } from "fp-ts/lib/Task";

type Env<R, E, A> = (r: R) => Task<Either<E, A>>;

const run = <R, E, A>(r: R, env: Env<R, E, A>) => env(r);

const of = <R, E, A>(a: A): Env<R, E, A> =>
    (r: R) => task.of(right(a));

const ask = <R>(): Env<R, void, R> =>
    (r: R) => task.of(right(r));

const map = <R, E, A, B>(f: (a: A) => B) => (fa: Env<R, E, A>): Env<R, E, B> =>
    (r: R) => run(r, fa).map(ea => ea.map(f));

const chain = <R, E, A, B>(fab: (a: A) => Env<R, E, B>, fa: Env<R, E, A>): Env<R, E, B> =>
    (r: R) =>
        //run fa
        //if it success, use the value to run fb
        //return as single env
        run(r, fa).chain(ea =>
            ea.fold(
                e => task.of(left<E, B>(e)),
                a => run(r, fab(a))
            )
        )

type ConsoleService = {
    writeLine: (s: string) => Env<ConsoleService, void, void>;
    readLine: () => Env<ConsoleService, void, string>;
}

const testConsoleService: ConsoleService = {
    writeLine: () => of(undefined),
    readLine: () => of('hi')
}

type ProgramEnv = ConsoleService;
const program: Env<ProgramEnv, void, string> = 
    chain(
        r => r.readLine(),
        ask<ProgramEnv>()
    );

//run the env then run the task
run(testConsoleService, program).run().then(result => {
    console.log("Result", result);
    //Result right("hi")
})