[Sync Iteration] javascript/ozans-playlist/1

solutions/javascript/ozans-playlist/1/ozans-playlist.js

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+// @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) {
+  let dedup = new Set(playlist);
+  return Array.from(dedup);
+}
+
+/**
+ * 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) {
+  let newPlaylist = new Set(playlist);
+  return newPlaylist.has(track);
+
+}
+
+/**
+ * Adds a track to a playlist.
+ *
+ * @param {string[]} playlist
+ * @param {string} track
+ * @returns {string[]} new playlist
+ */
+export function addTrack(playlist, track) {
+  let newPlsylist = new Set(playlist);
+  newPlsylist.add(track);
+  return Array.from(newPlsylist);
+}
+
+/**
+ * Deletes a track from a playlist.
+ *
+ * @param {string[]} playlist
+ * @param {string} track
+ * @returns {string[]} new playlist
+ */
+export function deleteTrack(playlist, track) {
+  let newPlaylist = new Set(playlist);
+  newPlaylist.delete(track);
+  return Array.from(newPlaylist);
+}
+
+/**
+ * Lists the unique artists in a playlist.
+ *
+ * @param {string[]} playlist
+ * @returns {string[]} list of artists
+ */
+export function listArtists(playlist) {
+  let uniqueArtist = new Set();
+  for (let item of playlist){
+    let [song, artist] = item.split(" - ");
+    uniqueArtist.add(artist);
+ }
+  return Array.from(uniqueArtist);
+}