ozans-playlist.js

// @ts-check
//
// The line above enables type checking for this file. Various IDEs interpret
// the @ts-check directive. It will give you helpful autocompletion when
// implementing this exercise.

/**
 * Removes duplicate tracks from a playlist.
 *
 * @param {string[]} playlist
 * @returns {string[]} new playlist with unique entries
 */
export function removeDuplicates(playlist) {
	return [...new Set(playlist)];
}

/**
 * Checks whether a playlist includes a track.
 *
 * @param {string[]} playlist
 * @param {string} track
 * @returns {boolean} whether the track is in the playlist
 */
export function hasTrack(playlist, track) {
	return playlist.includes(track);
}

/**
 * Adds a track to a playlist.
 *
 * @param {string[]} playlist
 * @param {string} track
 * @returns {string[]} new playlist
 */
export function addTrack(playlist, track) {
	playlist.push(track);
	return removeDuplicates(playlist);
}

/**
 * Deletes a track from a playlist.
 *
 * @param {string[]} playlist
 * @param {string} track
 * @returns {string[]} new playlist
 */
export function deleteTrack(playlist, track) {
	return playlist.filter(song => song != track);
}

/**
 * Lists the unique artists in a playlist.
 *
 * @param {string[]} playlist
 * @returns {string[]} list of artists
 */
export function listArtists(playlist) {
	const artists = playlist.map(track => {
		return track.split("-")[1].trim();
	});
	return removeDuplicates(artists);
}