drzhbe/app.js

## app.js
const API_KEY = 'eee301d58fa69f9c700b2aadfb915a71';
const BASE_URL = 'http://ws.audioscrobbler.com/2.0';

/* Fetch data */

function fetchArtist(artist) {
  const searchParams = `artist=${artist}&api_key=${API_KEY}&format=json`;

  fetch(`${BASE_URL}/?method=artist.gettopalbums&limit=5&${searchParams}`)
    .then(async response => {
      if (response.status !== 200) {
        return;
      }
      const data = await response.json();
      store.albumsMeta.set(data.topalbums.album);

      // Fetch the albums content
      const requests = store.albumsMeta.value.map(album =>
        fetch(`${BASE_URL}/?method=album.getinfo&album=${album.name}&${searchParams}`)
          .then(async response => {
            if (response.status !== 200) {
              return;
            }
            const data = await response.json();
            return data;
          })
      );
      const albums = await Promise.all(requests);
      store.albumsData.set(albums);
    });
  fetch(`${BASE_URL}/?method=artist.getTopTracks&limit=15&${searchParams}`)
    .then(async response => {
      if (response.status !== 200) {
        return;
      }
      const data = await response.json();
      store.tracks.set(data.toptracks.track);
    });
  fetch(`${BASE_URL}/?method=artist.getinfo&lang=ru&${searchParams}`)
    .then(async response => {
      if (response.status !== 200) {
        return;
      }
      const data = await response.json();
      store.bio.set(data.artist.bio);
    });
}

/* Utilities */

function getRandomItem(array) {
  return array[Math.floor(Math.random()*array.length)];
}

class Observable {
  constructor() {
    this.value = undefined;
    this.callbacks = [];
  }
  onChange(callback) {
    this.callbacks.push(callback);
  }
  set(value) {
    this.value = value;
    this.callbacks.forEach(cb => cb(value));
  }
}

/* Init */

const placeholders = [
  'nirvana', 'metallica', 'the doors', 'кино', 'u2',
  'сплин', 'ддт', 'the cure', 'soundgarden', 'nin', 'психея',
];
const searchInput = document.querySelector('.searchInput');
searchInput.placeholder = `Например ${getRandomItem(placeholders)}`;

document.querySelector('.searchButton').addEventListener('click', () => {
  fetchArtist(searchInput.value);
});

document.addEventListener('keydown', (e) => {
  if (e.keyCode === 13) { // enter
    fetchArtist(searchInput.value);
  }
});

const store = {
  albumsMeta: new Observable(),
  albumsData: new Observable(),
  tracks: new Observable(),
  bio: new Observable(),
};

/* Render the data from the store */

store.albumsMeta.onChange(albums => {
  const html = albums.map(album => {
    const name = album.name === '(null)'
        ? 'с этим альбомом что то не так'
        : album.name;
    const image = album.image[3]['#text'] || 'https://pp.userapi.com/smNSUs97pLs2BT0jiiKIdEy6uaCJ3lHadeuJsw/qnlRTo3pAb8.jpg?ava=1';
    return `<div class='item-album'><a href=${album.url}><div>${name}</div></a><img src=${image}></div>`;
  });

  document.querySelector('.albums').innerHTML = html.join('');
});

store.albumsData.onChange(albums => {
  const albumNodes = document.querySelectorAll('.item-album');
  albums.forEach((album, i) => {
    const tracksNode = document.createElement('ul');
    album.album.tracks.track.forEach(track => {
      const li = document.createElement('li');
      li.classList.add('album-track');
      li.innerText = track.name;
      tracksNode.appendChild(li);
    });

    const albumNode = albumNodes[i];
    albumNode.appendChild(tracksNode);
  });
});

store.tracks.onChange(tracks => {
  const html = tracks.map(({ url, name, playcount }) =>
    `<li><a href=${url}>${name}</a> прослушиваний ${playcount}</li>`
  );

  document.querySelector('.tracks').innerHTML = html.join('');
});

store.bio.onChange(bio => {
  document.querySelector('.bio').innerHTML = bio.content || `We know nothing about this artist`;
});

## index.html
<!DOCTYPE html>
<html>
<head>
  <title>Search your artist</title>
</head>
<body>
  <div class="app">
    <div class='searchLabel'>Введите название исполнителя</div>
    <input type="text" class='searchInput'>
    <button class='searchButton'>Найти</button>
    <h2>Топ 5 альбомов</h2>
    <div class='albums'></div>
    <h2>Топ 15 песен</h2>
    <div class='tracks'></div>
    <h2>Биография</h2>
    <div class='bio'></div>
  </div>
  <script src='app.js'></script>
</body>
</html>
	const API_KEY = 'eee301d58fa69f9c700b2aadfb915a71';
	const BASE_URL = 'http://ws.audioscrobbler.com/2.0';

	/* Fetch data */

	function fetchArtist(artist) {
	const searchParams = `artist=${artist}&api_key=${API_KEY}&format=json`;

	fetch(`${BASE_URL}/?method=artist.gettopalbums&limit=5&${searchParams}`)
	.then(async response => {
	if (response.status !== 200) {
	return;
	}
	const data = await response.json();
	store.albumsMeta.set(data.topalbums.album);

	// Fetch the albums content
	const requests = store.albumsMeta.value.map(album =>
	fetch(`${BASE_URL}/?method=album.getinfo&album=${album.name}&${searchParams}`)
	.then(async response => {
	if (response.status !== 200) {
	return;
	}
	const data = await response.json();
	return data;
	})
	);
	const albums = await Promise.all(requests);
	store.albumsData.set(albums);
	});
	fetch(`${BASE_URL}/?method=artist.getTopTracks&limit=15&${searchParams}`)
	.then(async response => {
	if (response.status !== 200) {
	return;
	}
	const data = await response.json();
	store.tracks.set(data.toptracks.track);
	});
	fetch(`${BASE_URL}/?method=artist.getinfo&lang=ru&${searchParams}`)
	.then(async response => {
	if (response.status !== 200) {
	return;
	}
	const data = await response.json();
	store.bio.set(data.artist.bio);
	});
	}

	/* Utilities */

	function getRandomItem(array) {
	return array[Math.floor(Math.random()*array.length)];
	}

	class Observable {
	constructor() {
	this.value = undefined;
	this.callbacks = [];
	}
	onChange(callback) {
	this.callbacks.push(callback);
	}
	set(value) {
	this.value = value;
	this.callbacks.forEach(cb => cb(value));
	}
	}

	/* Init */

	const placeholders = [
	'nirvana', 'metallica', 'the doors', 'кино', 'u2',
	'сплин', 'ддт', 'the cure', 'soundgarden', 'nin', 'психея',
	];
	const searchInput = document.querySelector('.searchInput');
	searchInput.placeholder = `Например ${getRandomItem(placeholders)}`;

	document.querySelector('.searchButton').addEventListener('click', () => {
	fetchArtist(searchInput.value);
	});

	document.addEventListener('keydown', (e) => {
	if (e.keyCode === 13) { // enter
	fetchArtist(searchInput.value);
	}
	});

	const store = {
	albumsMeta: new Observable(),
	albumsData: new Observable(),
	tracks: new Observable(),
	bio: new Observable(),
	};

	/* Render the data from the store */

	store.albumsMeta.onChange(albums => {
	const html = albums.map(album => {
	const name = album.name === '(null)'
	? 'с этим альбомом что то не так'
	: album.name;
	const image = album.image[3]['#text'] \|\| 'https://pp.userapi.com/smNSUs97pLs2BT0jiiKIdEy6uaCJ3lHadeuJsw/qnlRTo3pAb8.jpg?ava=1';
	return `<div class='item-album'><a href=${album.url}><div>${name}</div></a><img src=${image}></div>`;
	});

	document.querySelector('.albums').innerHTML = html.join('');
	});

	store.albumsData.onChange(albums => {
	const albumNodes = document.querySelectorAll('.item-album');
	albums.forEach((album, i) => {
	const tracksNode = document.createElement('ul');
	album.album.tracks.track.forEach(track => {
	const li = document.createElement('li');
	li.classList.add('album-track');
	li.innerText = track.name;
	tracksNode.appendChild(li);
	});

	const albumNode = albumNodes[i];
	albumNode.appendChild(tracksNode);
	});
	});

	store.tracks.onChange(tracks => {
	const html = tracks.map(({ url, name, playcount }) =>
	`<li><a href=${url}>${name}</a> прослушиваний ${playcount}</li>`
	);

	document.querySelector('.tracks').innerHTML = html.join('');
	});

	store.bio.onChange(bio => {
	document.querySelector('.bio').innerHTML = bio.content \|\| `We know nothing about this artist`;
	});
	<!DOCTYPE html>
	<html>
	<head>
	<title>Search your artist</title>
	</head>
	<body>
	<div class="app">
	<div class='searchLabel'>Введите название исполнителя</div>
	<input type="text" class='searchInput'>
	<button class='searchButton'>Найти</button>
	<h2>Топ 5 альбомов</h2>
	<div class='albums'></div>
	<h2>Топ 15 песен</h2>
	<div class='tracks'></div>
	<h2>Биография</h2>
	<div class='bio'></div>
	</div>
	<script src='app.js'></script>
	</body>
	</html>