Spotify Apps API - Get the top five tracks from five artists (JS)

spotify-apps-sandbox-top_artists_tracks.js

/* Instantiate the global sp object; include models & views */
var sp = getSpotifyApi(1);
var models = sp.require("sp://import/scripts/api/models");
var views = sp.require("sp://import/scripts/api/views");

var artists = ['Frank Sinatra', 'Drake', 'T-Pain', 'The Lonely Island', 'Avan Lava'];

var playlist = [];
var done = 0;

for(var i=0; i<artists.length; i++){
 
    var search = new models.Search('artist:"'+artists[i]+'"');
    search.localResults = models.LOCALSEARCHRESULTS.IGNORE;
    search.searchPlaylists = false;
    search.searchAlbums = false;
    search.pageSize = 5;

    search.observe(models.EVENT.CHANGE, function(result) {

        result.tracks.forEach(function(track) {
            playlist.push(track);
        });
        done++;

        if (done == artists.length) {
            console.log(playlist);
        }

    });

    search.appendNext();

}