Count the number of occurrences of each letter of the alphabet in a file

breeds.txt

Airedale Terrier, Terrier
Affenpinscher, Toy
Afghan Hound, Hound
Airedale Terrier, Terrier
Akita Inu, Working
Alaskan Malamute, Working
American English Coonhound, Hound
American Eskimo Dog (Miniature), Non-Sporting
American Eskimo Dog (Standard), Non-Sporting
American Eskimo Dog (Toy), Toy
American Foxhound, Hound
American Staffordshire Terrier, Terrier
American Water Spaniel, Sporting
Anatolian Shepherd Dog, Working
Australian Cattle Dog, Herding
Australian Shepherd, Herding
Australian Terrier, Terrier
Borzoi, Hound
Basenji, Hound
Basset Hound, Hound
Beagle, Hound
Bearded Collie, Herding
Beauceron, Herding
Bedlington Terrier, Terrier
Belgian Malinois, Herding
Belgian Sheepdog, Herding
Belgian Tervuren, Herding
Bergamasco, Herding
Bernese Mountain Dog, Working
Bichon Frisé, Non-Sporting
Black and Tan Coonhound, Hound
Black Russian Terrier, Working
Bloodhound, Hound
Bluetick Coonhound, Hound
Border Collie, Herding
Border Terrier, Terrier
Borzoi, Hound
Boston Terrier, Non-Sporting
Bouvier des Flandres, Herding
Boxer, Working
Boykin Spaniel, Sporting
Briard, Herding
Brittany (dog), Sporting
Brussels Griffon, Toy
Bull Terrier, Terrier
Bull Terrier (Miniature), Terrier
Bulldog, Non-Sporting
Bullmastiff, Working
Clumber Spaniel, Sporting
Cairn Terrier, Terrier
Canaan Dog, Working
Cane Corso, Working
Cardigan Welsh Corgi, Herding
Cavalier King Charles Spaniel, Toy
Cesky Terrier, Terrier
Chesapeake Bay Retriever, Sporting
Chihuahua, Toy
Chinese Crested Dog, Toy
Chinese Shar Pei, Non-Sporting
Chow Chow, Non-Sporting
Clumber Spaniel, Sporting
Cocker Spaniel, Sporting
Collie, Herding
Curly-Coated Retriever, Sporting
Dogue de Bordeaux
Dachshund, Hound
Dalmatian, Non-Sporting
Dandie Dinmont Terrier, Terrier
Doberman Pinscher, Working
Dogue de Bordeaux, Working
English Cocker Spaniel, Sporting
English Foxhound, Hound
English Setter, Sporting
English Springer Spaniel, Sporting
English Toy Spaniel, Toy
Field Spaniel
Field Spaniel, Sporting
Finnish Lapphund, Herding
Finnish Spitz, Non-Sporting
Flat-Coated Retriever, Sporting
French Bulldog, Non-Sporting
Greyhound
German Pinscher, Working
German Shepherd Dog, Herding
German Shorthaired Pointer, Sporting
German Wirehaired Pointer, Sporting
Giant Schnauzer, Working
Glen of Imaal Terrier, Terrier
Golden Retriever, Sporting
Gordon Setter, Sporting
Great Dane, Working
Great Pyrenees, Working
Greater Swiss Mountain Dog, Working
Greyhound, Hound
Harrier, Hound
Havanese, Toy
Irish Terrier
Ibizan Hound, Hound
Icelandic Sheepdog, Herding
Irish Red and White Setter, Sporting
Irish Setter, Sporting
Irish Terrier, Terrier
Irish Water Spaniel, Sporting
Irish Wolfhound, Hound
Italian Greyhound, Toy
Japanese Chin, Toy
Keeshond, Non-Sporting
Kerry Blue Terrier, Terrier
Komondor, Working
Kuvasz, Working
Labrador Retriever
Labrador Retriever, Sporting
Lakeland Terrier, Terrier
Leonberger, Working
Lhasa Apso, Non-Sporting
Löwchen, Non-Sporting
Miniature Schnauzer puppy
Maltese, Toy
Manchester Terrier, Terrier & Toy
Mastiff, Working
Miniature Bull Terrier, Terrier
Miniature Pinscher, Toy
Miniature Schnauzer, Terrier
Nova Scotia Duck-Tolling Retriever
Neapolitan Mastiff, Working
Newfoundland, Working
Norfolk Terrier, Terrier
Norwegian Buhund, Herding
Norwegian Elkhound, Hound
Norwich Terrier, Terrier
Nova Scotia Duck-Tolling Retriever, Sporting
Old English Sheepdog, Herding
Otterhound, Hound
Pharaoh Hound
Papillon, Toy
Parson Russell Terrier, Terrier
Pekingese, Toy
Pembroke Welsh Corgi, Herding
Petit Basset Griffon Vendéen, Hound
Pharaoh Hound, Hound
Plott, Hound
Pointer, Sporting
Polish Lowland Sheepdog, Herding
Pomeranian, Toy
Poodle
Portuguese Water Dog, Working
Pug, Toy
Puli, Herding
Pyrenean Shepherd, Herding
Redbone Coonhound, Hound
Rhodesian Ridgeback, Hound
Rottweiler, Working
St. Bernard, Working
Saluki, Hound
Samoyed, Working
Schipperke, Non-Sporting
Scottish Deerhound, Hound
Scottish Terrier, Terrier
Sealyham Terrier, Terrier
Shetland Sheepdog, Herding
Shiba Inu, Non-Sporting
Shih Tzu, Toy
Siberian Husky, Working
Silky Terrier, Toy
Skye Terrier, Terrier
Smooth Fox Terrier, Terrier
Soft-Coated Wheaten Terrier, Terrier
Spinone Italiano, Sporting
Staffordshire Bull Terrier, Terrier
Standard Schnauzer, Working
Sussex Spaniel, Sporting
Swedish Vallhund, Herding
Tibetan Mastiff, Working
Tibetan Spaniel, Non-Sporting
Tibetan Terrier, Non-Sporting
Toy Fox Terrier, Toy
Vizsla, Sporting
West Highland White Terrier
Weimaraner, Sporting
Welsh Springer Spaniel, Sporting
Welsh Terrier, Terrier
West Highland White Terrier, Terrier
Whippet, Hound
Wire Fox Terrier, Terrier
Wirehaired Pointing Griffon, Sporting
Yorkshire Terrier, Toy

script.js

#!/usr/bin/env node
var fs = require('fs');

var alphabet = {
  a: 0,
  b: 0,
  c: 0,
  d: 0,
  e: 0,
  f: 0,
  g: 0,
  h: 0,
  i: 0,
  j: 0,
  k: 0,
  l: 0,
  m: 0,
  n: 0,
  o: 0,
  p: 0,
  q: 0,
  r: 0,
  s: 0,
  t: 0,
  u: 0,
  v: 0,
  w: 0,
  x: 0,
  y: 0,
  z: 0
};

fs.readFile('./breeds.txt', 'utf8', function (err, data) {
  if (err) { console.log(err); return; }

  for (var i = 0; i < data.length; i++) {
    if (Object.keys(alphabet).indexOf(data[i].toLowerCase()) !== -1) {
      var letter = data[i].toLowerCase();
      alphabet[letter]++;
    }
  }

  console.log(alphabet);
});