Merge pull request #3 from apollographql-education/lh/final-updates

update resolvers and add method to spotify api

src/datasources/spotify-api.ts

@@ -1,6 +1,5 @@
 import { RESTDataSource } from "@apollo/datasource-rest";
-import { Playlist } from "../types"
-import { PlaylistModel, SnapshotOrError } from '../models'
+import { PlaylistModel, TrackModel, SnapshotOrError } from '../models'
 
 export class SpotifyAPI extends RESTDataSource {
   baseURL = "https://spotify-demo-api-fe224840a08c.herokuapp.com/v1/";
@@ -13,6 +12,12 @@ export class SpotifyAPI extends RESTDataSource {
     }>("browse/featured-playlists");
 
     return response?.playlists?.items ?? [];
+
+  }
+
+  async getTracks(playlistId: string): Promise<TrackModel[]> {
+    const response = await this.get<{ items: { track: TrackModel }[] }>(`playlists/${playlistId}/tracks`)
+    return response?.items?.map(({track}) => track) ?? [];
   }
 
   getPlaylist(playlistId: string): Promise<PlaylistModel> {

src/resolvers.ts

@@ -39,9 +39,8 @@ export const resolvers: Resolvers = {
     },
   },
   Playlist: {
-    tracks: ({ tracks }) => {
-      const { items = [] } = tracks;
-      return items.map(({ track }) => track);
+    tracks: async ({ tracks, id }, _, { dataSources }) => {
+      return tracks.items ? tracks.items.map(({track}) => track) : dataSources.spotifyAPI.getTracks(id);
     }
   },
   Track: {