docs: add a more complete download example

examples/download/index.ts

@@ -1,24 +1,44 @@
-import { createWriteStream } from 'fs';
 import { Innertube, UniversalCache } from 'youtubei.js';
+import { readFileSync, existsSync, mkdirSync, createWriteStream } from 'fs';
 
 (async () => {
   const yt = await Innertube.create({ cache: new UniversalCache() });
   
-  const info = await yt.getBasicInfo('jLTOuvBTLxA');
+  const search = await yt.music.search('No Copyright Background Music', { type: 'album' });
   
-  const stream = await info.download({
-    type: 'audio',
-    quality: 'best',
-    format: 'mp4'
-  });
+  if (!search.results)
+    throw new Error('Filter "type" must be used');
+    
+  const album = await yt.music.getAlbum(search.results[0].id as string);
   
-  console.info(`Downloading ${info.basic_info.title}...`);
-
-  const file = createWriteStream(`${info.basic_info.title}.m4a`);
+  if (!album.contents)
+    throw new Error('Album appears to be empty');
+    
+  console.info(`Album "${album.header.title.toString()}" by ${album.header.author?.name}`, '\n');
   
-  for await (const chunk of streamToIterable(stream)) {
-    file.write(chunk);
+  for (const song of album.contents) {
+    const stream = await yt.download(song.id as string, {
+      type: 'audio', // audio, video or audio+video
+      quality: 'best' // best, bestefficiency, 144p, 240p, 480p, 720p and so on.
+      format: 'mp4' // media container format 
+    });
+    
+    console.info(`Downloading ${song.title} (${song.id})`);
+    
+    const dir = `./${album.header.title.toString()}`;
+    
+    if (!existsSync(dir)) {
+      mkdirSync(dir);
+    }
+    
+    const file = createWriteStream(`${dir}/${song.title?.replace(/\//g, '')}.m4a`);
+  
+    for await (const chunk of streamToIterable(stream)) {
+      file.write(chunk);
+    }
+    
+    console.info(`${song.id} - Done!`, '\n');
   }
   
-  console.info('Done!');
+  console.info(`Downloaded ${album.header.song_count}!`);
 })();