anagram

anagram.js

function anagram(word) {
  this.word = word;
  this.originalWord = wordObject(word);
  this.matches = function (wordArray) {
    if (typeof wordArray === 'string'){
      wordArray = Array.prototype.slice.call(arguments);
    }
    var wordMatches = [];
    for (var i = 0; i < wordArray.length; i++) {
      var wordMatcher = wordArray[i];
      if (this.word.length !== wordMatcher.length || this.word.toLowerCase() === wordMatcher.toLowerCase()) {
        continue;
      }
      var wordToCheck = wordObject(wordMatcher);
      if (checkWords(this.originalWord, wordToCheck)) {
        wordMatches.push(wordMatcher)
      }
    }
    return wordMatches;
  };
}

function checkWords(word1, word2) {
  if (Object.keys(word1).length != Object.keys(word2).length) {
    return false;
  }
  for (len in word1) {
    if (!word1.hasOwnProperty(len)) {
      continue;
    }
    if (word1[len] !== word2[len]) {
      return false;
    }
  }
  return true;
}

function wordObject(word) {
  var charArray = word.split('');
  var charCount = {};
  for (i = 0; i < charArray.length; i++) {
    var char = charArray[i].toLowerCase();
    if (typeof charCount[char] === "number") {
      charCount[char]++;
    } else {
      charCount[char] = 1;
    }
  }
  return charCount;
}

module.exports = anagram;

anagram_test.spec.js

var anagram = require('./anagram');

describe('Anagram', function() {

  it("no matches",function() {
    var subject = new anagram("diaper");
    var matches = subject.matches([ "hello", "world", "zombies", "pants"]);

    expect(matches).toEqual([]);
  });

  it("detects simple anagram",function() {
    var subject = new anagram("ant");
    var matches = subject.matches(['tan', 'stand', 'at']);

    expect(matches).toEqual(['tan']);
  });

  it("does not detect false positives",function() {
    var subject = new anagram("galea");
    var matches = subject.matches(["eagle"]);

    expect(matches).toEqual([]);
  });

  it("detects multiple anagrams",function() {
    var subject = new anagram("master");
    var matches = subject.matches(['stream', 'pigeon', 'maters']);

    expect(matches).toEqual(['stream', 'maters']);
  });

  it("does not detect anagram subsets",function() {
    var subject = new anagram("good");
    var matches = subject.matches(['dog', 'goody']);

    expect(matches).toEqual([]);
  });

  it("detects anagram",function() {
    var subject = new anagram("listen");
    var matches = subject.matches(['enlists', 'google', 'inlets', 'banana']);

    expect(matches).toEqual(['inlets']);
  });

  it("detects multiple anagrams",function() {
    var subject = new anagram("allergy");
    var matches = subject.matches(['gallery', 'ballerina', 'regally', 'clergy', 'largely', 'leading']);

    expect(matches).toEqual(['gallery', 'regally', 'largely']);
  });

  it("detects anagrams case-insensitively",function() {
    var subject = new anagram("Orchestra");
    var matches = subject.matches(['cashregister', 'Carthorse', 'radishes']);

    expect(matches).toEqual(['Carthorse']);
  });

  it("does not detect a word as its own anagram",function() {
    var subject = new anagram("banana");
    var matches = subject.matches(['Banana']);

    expect(matches).toEqual([]);
  });

  it("matches() accepts string arguments",function() {
    var subject = new anagram("ant");
    var matches = subject.matches("stand", "tan", "at");

    expect(matches).toEqual(["tan"]);
  });

});