index.js

'use strict'
var fs = require('fs'),
    Task = require('data.task'),
    util = require('util'),
    { 
      curry, 
      map, 
      sequence, 
      toString, 
      unnest, 
    }  = require('ramda');

// readDirectories :: String -> Task (Array String)
function readDirectories(path){
  return new Task(function(reject, resolve){
    fs.readdir(path, function(err, filenames){
      err == null ? resolve(filenames) : reject(err);
    });
  });
};

// readFile :: String -> Task String
function readFile(directory, file){
  return new Task(function(reject, resolve){
    fs.readFile(
      directory + file, 
      'utf8',  
      function(err, data){
        err == null ? resolve(data) : reject(err);
      }
    )
  })
};

//  parseFile :: String -> { name :: String
//                         , age  :: Number }
function parseFile(data){
  data = data.trim();
  var tokens = data.split(',');
  return {name: tokens[0], age: tokens[1]} 
};

var dirname = './sample_data/',
//  dirs :: Task (Array String)
    dirs = readDirectories(dirname),
//  files :: Task (Array (Task String))
    cReadFile = curry(readFile),
    files = map(map(cReadFile(dirname)), dirs),
//  sequenced :: Task (Task (Array String))
    sequenced = map(sequence(Task.of), files),
//  unnested  :: Task (Array String)
    unnested = unnest(sequenced),
//  parsed :: Task (Array { name :: String
//                        , age :: Number }
    parsed = map(map(parseFile), unnested);

parsed.fork(
    function(err){
      process.stderr.write(err.message);
      process.exit(1);
    },
    function(data){
      process.stdout.write(toString(data));
      process.exit(0);
    }
);

module.exports = {
  example: function example(){
    return true
  }
}

test.js

var test = require('tape').test,
    example = require('./index.js');


test('add: add two numbers correctly', function(t){
  var actual = 3,
      expected = actual;
  t.equal(actual, expected);
  t.end();
});
test('example: sample exported function returns true', function(t){
  var actual = example.example(),
      expected = true;
  t.equal(actual, expected);
  t.end();
});