Script to map questions to answers on surveys.

survey.js

/**
 * @author John Molina <jmolina@pixnabilab.com>
 * Creates a Survey class that gathers data based on chosen answers and returns
 * a key object that will be mapped against a dictionary of answers.
 * @class
 * @param {Object} answers
 */
class Survey extends EventEmitter {
  constructor(answers) {
    super()

    this.scope = this
    this.answers = answers
    /**
     * Traversing question tree. Used to indicate which questions to ask
     * @constant
     * @type {Array}
     */
    this.questionSteps = []
    this.questions = {}

    /**
     * Tracks current question through setQuestion event
     * @type {object}
     */
    this.q = null
    this.counter = 0
    this.answer = null

    this.on('setQuestion', this.setQuestion)
    this.on('setAnswer', this.setAnswer)
  }
	
	setQuestion() {
		if (!Object.is(this.q, this.questions[this.counter]))
    	this.q = this.questions[this.counter]
	}
	
	/**
	 * Set new answer
	 * @param {String} answer
	 */
	setAnswer(answer) {
		this.answer = this.answers[answer]
	}

  /**
   * Set new question
   * @param {Number|String} key
   */
  addQuestion(key) {
    if (isFinite(key))
      this.questions[key] = { value: null, collection: [] }
    else
      throw new Error('Wrong key assignment for question')

    this.emit('setQuestion')
  }

  get handlers() {
    const scope = this

    return {
     /**
      * Update collection values, such as checkboxes
      * @param  {Number} i Index value of the current value in the collection
      * @param  {Number} v Add/Subtract current collection question value
      * @return {Number}   Updated question value
      */
      multiples() {
        const { q } = scope

        try {
          let cLength = q.collection.length
          let cIntegers = q.collection.filter(Number.isInteger)
          let total = cIntegers.reduce((v1, v2) => v1 + v2)

          if (cIntegers.length > 1) ++total

          q.value = total
        } catch(e) {
          q.value = 0
        }

        scope.emit('setQuestion')
        return q
      },
      /**
       * Update current question value
       * @param  {Number} v New value
       * @return {Number}   New assigned value to the current question
       */
      update(v) {
        scope.emit('setQuestion')
        scope.q.value = parseInt(v)
        return scope.q
      }
    }
  }
  /**
   * Returns all questions objects as enum
   * @return {Array.<questions>}
   */
  *[Symbol.iterator]() {
    for (let k of Object.keys(this.questions)) {
      yield this.questions[k]
    }
  }
  /**
   * Collect all question values and return in dictionary format
   * @return {String}
   */
  constructAnswer() {
    const answer = [...this].map(({ value }) => value - 1).join('-')
    return this.emit('setAnswer', answer)
  }
}

const answers = [
	'First Answer',
	'Second Answer',
	'Third Answer',
	'Fourth Answer'
]

/* Create delegations */
const delegations = {
  /* Internet */
  '0-0-0': answer[0],
  '1-0-0': answer[1],
  '0-1-0': answer[2],
  '0-0-1': answer[2],
  '1-1-0': answer[3]
}