index.js

var _ = require('lodash');
var fs = require('fs');
var path = require('path');
var byline = require('byline');

var anagrams = {}, matchers = [];

function findAnagrams (filePath, cb) {
  byline(fs.createReadStream(filePath, { encoding: 'utf8' }))
    .on('data', process)
    .on('end', function() {
      cb(removeEmptyAnagrams())
    })
}

function process (word) {
  var sortedWord = sortLettersAlphabetically(word)
  if (anagrams[sortedWord]) {
    anagrams[sortedWord].push(word)
  } else {
    anagrams[sortedWord] = [word]
  }
}

function sortLettersAlphabetically (word) {
  return word.toLowerCase().split("").sort().join("")
}

module.exports = findAnagrams;