JoaoCnh

Yup.object().shape({
  email: Yup.string().email('Invalid email address').required('Email is required!'),
  username: Yup.string().required('This man needs a username').when('email', (email, schema) => {
    if (email === 'foobar@example.com') { return schema.min(10); }
    return schema;
  }),
});

JoaoCnh

var allSongNames = songs.map(function (song) {
  return song.name;  
});

// ES6
const allSongNames = songs.map(song => {
  return song.name;
});

console.log(allSongNames); // ["Curl of the Burl","Oblivion","Flying Whales","L'Enfant Sauvage"];

JoaoCnh

var strings = ["hello", "Matt", "Mastodon", "Cat", "Dog"];

var filtered = strings.filter(function (str) {
  return str.includes("at");
});

// ES6
const filtered = strings.filter(str => {
  return str.includes("at");

JoaoCnh

                          // Let's reduce the array of arrays into a single one
const songNames = allSongs.reduce((acc, currValue) => {
                            return acc.concat(currValue);
                          }, [])
                          // Let's map it out with the seconds turned into minutes 
                          .map(song => {
                            return { ...song, duration: Math.floor(song.duration / 60) };
                          })
                          // Let's filter the ones under 3 minutes
                          .filter(song => {

JoaoCnh

const mult = [songs, [{id: 112, name: "Chop Suey", artist: "System of a Down" }]];

var flatMult = mult.reduce(function (acc, currValue) {
  return acc.concat(currValue);
}, []);

// ES6
const flatMult = mult.reduce((acc, currValue) => {
  return acc.concat(currValue);
}, []);

JoaoCnh

var obj = songs.reduce(function (acc, currValue) {
  var artist = currValue.artist;
  var artistCount = acc[artist] ? acc[artist] + 1 : 1;
  
  var newObj = {};
  newObj[artist] = artistCount;
  
  return Object.assign(acc, newObj);
}, {});

JoaoCnh

const spotifySongs = [
  { id: 1, name: "Curl of the Burl", artist: "Mastodon", duration: 204 },
  { id: 2, name: "Oblivion", artist: "Mastodon", duration: 306 },
  { id: 3, name: "Flying Whales", artist: "Gojira", duration: 444 },
  { id: 4, name: "L'Enfant Sauvage", artist: "Gojira", duration: 246 }
];

const lastFmSongs = [
  { id: 5, name: "Chop Suey", artist: "System of a Down", duration: 192 },
  { id: 6, name: "Throne", artist: "Bring me the Horizon", duration: 186 },

JoaoCnh

const lowerCaseSongs = songs.map(mySongFunc);

var mySongFunc = function(song) {
  return song.name.toLowerCase();
};

// ES6
const mySongFunc = song => {
  return song.name.toLowerCase();
};

JoaoCnh

const songs = [
  {
    id: 1,
    name: "Curl of the Burl",
    artist: "Mastodon",
  },
  {
    id: 2,
    name: "Oblivion",
    artist: "Mastodon",

JoaoCnh

var mapped = songs.map(function (song) {
  // using _.omit we remove the artist property
  // don't use delete because it mutates the song object
  // while _.omit creates a new one
  var newSong = _.omit(song, "artist");
  
  return Object.assign(newSong, {
    scrobbleCount: 0,
    spotifyUrl: "let's just imagine these properties make sense for now",
  });