Anagram Dictionary

anagram.js

import _, {reject, every, includes} from 'lodash'

const dictionary = [ "a", "sand", "car", "ester", "reset", "steer", "terse", "trees" ]

export function getMatches(characterString) {
  let characters = characterString.split("")

  return reject(dictionary, (entry) => {
    return !every(characters, (character) => {
      return includes(entry, character)
    });
  });
}

export function createEntry(dict = {}, chars, word) {
  let firstChar = _(chars).first(),
      restChars = _(chars).slice(1).value()

  if(restChars.length === 0) {
    if(dict[firstChar])
      dict[firstChar].values.push(word)
    else
      dict[firstChar] = {values: [word]}
    return dict;
  } else {
    dict[firstChar] = createEntry(dict[firstChar], restChars, word)
    return dict
  }
}

export function createDictionary(words) {
  return _.transform(words, (memo, word) => {
    memo = createEntry(memo, word.split("").sort(), word)
  }, {})
}

anagram.test.js

require('babel-register')
var expect = require('chai').expect
var _ = require('lodash')

var AnagramDetector = require('anagram_detector')

describe("Anagram detector", () => {

  describe.only("createDictionary", () => {
    it("adds all values to the dictionary", () => {
      var words = ["asp", "sap"]
      var res = AnagramDetector.createDictionary(words)
      expect(res.a.p.s.values).to.contain.all("asp", "sap")
    })
  })

  describe.only("createEntry", () => {
    it("adds to values array if node exists", () => {
      var word = "asp"
      var dict = {a: {p: {s: {values: ["sap"]}}}}
      var res = AnagramDetector.createEntry(dict, word.split("").sort(), "asp")
      expect(res.a.p.s.values).to.contain.all("asp", "sap")
    })

    it("add words to existing dictionary", () => {
      var word = "cap"
      var dict = {a: {c: {r: {values: ["car"]}}}}
      var res = AnagramDetector.createEntry(dict, word.split("").sort(), word)
      expect(res.a.c.p.values).to.contain("cap")
      expect(res.a.c.r.values).to.contain("car")
    })

    it("adds to existing nodes", () => {
      var word = "as"
      var dict = { }
      var res = AnagramDetector.createEntry(dict, word.split("").sort(), word)

      expect(res.a.s.values).to.contain("as")
    })
  })


  describe("getMatches", () => {
    it("returns all possible matches for given word", () => {
      const res = AnagramDetector.getMatches("steer")
            expect(res.length).to.equal(5)
    })

    it("doesn't return nonmatches", () => {
      const res = AnagramDetector.getMatches("steer")
      expect(res).to.not.contain("bar")
    })

    it("returns [] when there are no matches", () => {
      const res = AnagramDetector.getMatches("bar")
      expect(res).to.eql([])
    })

  })
})

test_results.txt

> usnode@1.0.0 test /Users/matt/Workspace/romanmt/union_station/node
> NODE_PATH=src mocha test/**/*.test.js


  Anagram detector
    createDictionary
      ✓ adds all values to the dictionary
    createEntry
      ✓ adds to values array if node exists
      ✓ add words to existing dictionary
      ✓ adds to existing nodes


  4 passing (40ms)