ES6 sample code

defaults-rest-spread-es5.js

import Ember from 'ember';

export default Ember.Object.extend({
  gtCountry: { code: 'GT', region: 'LATAM' },
  usCountry: { code: 'US', region: 'NA' },

  filterByRegion(region) {
    // adiós al "arguments" objeto. No más conversiones a arrays!
    const countries = Array.prototype.slice.call(arguments, 1);
    const filtereCountries = countries.filter((country) => country.region === region);

    // no más .apply sobre nuestras funciones
    this.notifyToFirstTwoCountries.apply(this, filteredCountries);

    return filteredCountries;
  },

  notifyToFirstTwoCountries(firstCountry, secondCountry) {},

  applyFilters(region) {
    // no más a reasignación condicional de parametros
    region = region || 'LATAM';

    return this.filterByRegion(region, this.get('gtCountry'), this.get('usCountry'));
  }
});

defaults-rest-spread-es6.js

import Ember from 'ember';

export default Ember.Object.extend({
  gtCountry: { code: 'GT', region: 'LATAM' },
  usCountry: { code: 'US', region: 'NA' },

  filterByRegion(region, ...countries) { // rest parameters
    const filteredCountries = countries.filter((country) => country.region === region);
    this.notifyToFirstTwoCountries(...filteredCountries); // spread operator

    return filteredCountries;
  },

  notifyToFirstTwoCountries(firstCountry, secondCountry) {},

  applyFilters(region = 'LATAM') {
    return this.filterByRegion(region, this.get('gtCountry'), this.get('usCountry'));
  }
});

destructuring.js

import Ember from 'ember';

const countries = [ 'Guatemala', 'United States' ];

// object destructuring
const {
  $,
  RSVP,
  inject: { service }
} = Ember;

// array destructuring
const [ guatemala, usa ] = countries;

// sustituye los patrones
const $ = Ember.$;
const service = Ember.inject.service;
const RSVP = Ember.RSVP;

const guatemala = countries[0];
const usa = countries[1];

methods-shorthands-es5.js

import Ember from 'ember';

export default Ember.Object.extend({
  countries: [
    // a lot of countries defined here
  ],

  filterByRegion: function(region) {
    const countries = this.get('countries').findBy('region', region);

    return {
      region: region,
      countries: countries
    };
  }
});

methods-shorthands-es6.js

import Ember from 'ember';

export default Ember.Object.extend({
  countries: [
    // a lot of countries defined here
  ],

  filterByRegion(region) {
    const countries = this.get('countries').findBy('region', region);

    return {
      region,
      countries
    };
  }
});

string-arrows-computed-es5.js

import Ember from 'ember';

export default Ember.Object.extend({
  getRegionDescription(region) {},

  fetchCountries(region) {
    const self = this;

    return fetch('/api/countries/' + region)
    .then(function parseRegionValues(countries) {
      const countriesByRegion = {};
      countriesByRegion[region] = {
        label: self.getRegionDescription(region),
        countries: countries
      };

      return countriesByRegion;
    });
  }
});

string-arrows-computed-es6.js

import Ember from 'ember';

export default Ember.Object.extend({
  getRegionDescription(region) {},

  fetchCountries(region) {
    return fetch(`/api/countries/${region}`)
    .then((countries) => {
      return {
        [region]: {
          label: this.getRegionDescription(region),
          countries
        }
      };
    });
  }
});