My Reader Monad Oop Impl

readerMonadOop.ts

interface IReader<D, A> {
  map<B>(f: (value: A) => B): IReader<D, B>,
  flatMap<B>(f: (value: A) => IReader<D, B>): IReader<D, B>,
  run(deps: D): A
}

const Reader = <D, A>(fn: (deps: D) => A): IReader<D, A> => {
  const run = (deps: D) => fn(deps);
  return {
    map: f => Reader((deps: D) => f(run(deps))),
    flatMap: f => Reader((deps: D) => f(run(deps)).run(deps)),
    run
  }
};