coroutines-bluebird.js

'use strict';

const bluebird      = require ('bluebird');

const exit0         = require ('./common/exit0');
const exit1         = require ('./common/exit1');
const join          = require ('./common/join');
const readFile      = require ('./common/read-file-promise');
const S             = require ('./common/sanctuary');


//    concatFiles :: (String -> String) -> Promise Error String
const concatFiles = bluebird.coroutine (function* generator(path) {
  const index = yield readFile (path ('index.txt'));
  const filenames = S.map (path) (S.lines (index));
  const results = yield bluebird.all (S.map (readFile) (filenames));
  return S.joinWith ('') (results);
});


const main = () => {
  concatFiles (join (process.argv[2]))
  .then (exit0, exit1);
};

if (process.mainModule.filename === __filename) main ();