Minor linting errors

[melissamcewen]

The linter, which is built in, caught these errors and logged them to the console (available both on the terminal and in the browser). They are very minor and can easily be cleaned up:

webpackHotDevClient.js:138 ./src/index.js
  Line 1:  'Component' is defined but never used  no-unused-vars
printWarnings @ webpackHotDevClient.js:138
webpackHotDevClient.js:138 ./src/util/Spotify.js
  Line 4:   'urlAccessToken' is assigned a value but never used  no-unused-vars
  Line 5:   'urlExpiresIn' is assigned a value but never used    no-unused-vars
  Line 59:  'playlistId' is assigned a value but never used      no-unused-vars
printWarnings @ webpackHotDevClient.js:138

Here is what the solution Spotify.js looks like in case you're curious

const clientId = ''; // Insert client ID here.
const redirectUri = '';//callbackHave to add this to your accepted Spotify redirect URIs on the Spotify API.
let accessToken;

const Spotify = {
  getAccessToken() {
    if (accessToken) {
      return accessToken;
    }

    const accessTokenMatch = window.location.href.match(/access_token=([^&]*)/);
    const expiresInMatch = window.location.href.match(/expires_in=([^&]*)/);
    if (accessTokenMatch && expiresInMatch) {
      accessToken = accessTokenMatch[1];
      const expiresIn = Number(expiresInMatch[1]);
      window.setTimeout(() => accessToken = '', expiresIn * 1000);
      window.history.pushState('Access Token', null, '/'); // This clears the parameters, allowing us to grab a new access token when it expires.
      return accessToken;
    } else {
      const accessUrl = `https://accounts.spotify.com/authorize?client_id=${clientId}&response_type=token&scope=playlist-modify-public&redirect_uri=${redirectUri}`;
      window.location = accessUrl;
    }
  },

  search(term) {
    const accessToken = Spotify.getAccessToken();
    return fetch(`https://api.spotify.com/v1/search?type=track&q=${term}`, {
      headers: {
        Authorization: `Bearer ${accessToken}`
      }
    }).then(response => {
      return response.json();
    }).then(jsonResponse => {
      if (!jsonResponse.tracks) {
        return [];
      }
      return jsonResponse.tracks.items.map(track => ({
        id: track.id,
        name: track.name,
        artist: track.artists[0].name,
        album: track.album.name,
        uri: track.uri
      }));
    });
  },

  savePlaylist(name, trackUris) {
    if (!name || !trackUris.length) {
      return;
    }

    const accessToken = Spotify.getAccessToken();
    const headers = { Authorization: `Bearer ${accessToken}` };
    let userId;

    return fetch('https://api.spotify.com/v1/me', {headers: headers}
    ).then(response => response.json()
    ).then(jsonResponse => {
      userId = jsonResponse.id;
      return fetch(`https://api.spotify.com/v1/users/${userId}/playlists`, {
        headers: headers,
        method: 'POST',
        body: JSON.stringify({name: name})
      }).then(response => response.json()
      ).then(jsonResponse => {
        const playlistId = jsonResponse.id;
        return fetch(`https://api.spotify.com/v1/users/${userId}/playlists/${playlistId}/tracks`, {
          headers: headers,
          method: 'POST',
          body: JSON.stringify({uris: trackUris})
        });
      });
    });
  }
};

export default Spotify;