ES6 javascript solution for https://www.hackerrank.com/challenges/ctci-ransom-note/problem

RansomNote.js

#!/usr/bin/env node

class RansomNote {
  constructor(words, magazineWords) {
    this.words = this.parseDocument(words)
    this.magazine = this.parseDocument(magazineWords)
  }

  parseDocument(words) {
    var wordHash = {}
    words.forEach((w) => {
      if (!wordHash[w]) { wordHash[w] = 0 }
      wordHash[w]++
    })
    return wordHash
  }

  validMagazine() {
    let {words, magazine} = this
    if (Object.keys(words).length < 0 || Object.keys(magazine).length < 0) {
        return 'No'
    }

    for (var key of Object.keys(words)) {
      if (magazine[key] >= words[key]) {
        continue
      } else {
        return 'No'
      }
    }
    return 'Yes'
  }
}

let magazineWords = "apgo clm w lxkvg mwz elo bg elo lxkvg elo apgo apgo w elo bg".split(' ')
let ransomWords = "elo lxkvg bg mwz clm w".split(' ')
let note = new RansomNote(ransomWords, magazineWords)

console.dir(note)
console.log("valid: ", note.validMagazine())