Cat files in folder

catDir.js

const { readdir, readFile, stat } = require('fs-extra');
const { Future } = require('ramda-fantasy');
const { traverse, join, curry } = require('ramda');

//:: String -> Future Error [String]
const ls = path => Future((reject, resolve) =>
    readdir(path, (err, files) => err ? reject(err) : resolve(files)));

//:: String -> Future Error String
const cat = curry((path, file) => Future((reject, resolve) =>
  readFile(`${path}/${file}`, 'utf8', (err, data) => err ? reject(err) : resolve(data))));

//:: String -> Future Error String
const catDir = dir => ls(dir).chain(traverse(Future.of, cat(dir))).map(join('\n'));

catDir('./texts').fork(console.error, console.log);