Feature: Added bulk lookups

README.md

@@ -83,7 +83,7 @@ the item's details.
 - [Lookup API docs](https://developer.apple.com/library/archive/documentation/AudioVideo/Conceptual/iTuneSearchAPI/LookupExamples.html)
 
 
-**ID params**
+#### ID params
 
 - amgAlbumId
 - amgArtistId
@@ -105,6 +105,19 @@ searchitunes( { id: 123456 } )
 ```
 
 
+#### Bulk lookup
+
+To request multiple objects at once you set one of the ID params above to an
+_array_ with the item ID's. This will always return an _array_.
+
+```js
+searchitunes( { id: [ 123, 789 ] } )
+  .then( arr => arr.forEach( processItems )
+  .catch( console.error )
+;
+```
+
+
 ## Unlicense
 
 This is free and unencumbered software released into the public domain.

searchitunes.js

@@ -24,7 +24,6 @@ module.exports = async function SearchItunes ( {
   trackId,
 
 } ) {
-  let first;
 
   let params = arguments[0];
   let url = 'https://itunes.apple.com/search';
@@ -56,11 +55,25 @@ module.exports = async function SearchItunes ( {
     'upc',
   ];
 
-  const hasKeys = Object.keys( params ).some( key => idKeys.includes( key ) );
+  let bulkRequest = false;
+  let idKey = false;
+  let key;
 
-  if ( hasKeys ) {
-    url = 'https://itunes.apple.com/lookup';
-    first = true;
+  for ( let i = 0; i < idKeys.length; i++ ) {
+    key = idKeys[i];
+
+    if ( params[key] ) {
+      idKey = true;
+      url = 'https://itunes.apple.com/lookup';
+
+      // Bulk request
+      if ( Array.isArray( params[key] ) ) {
+        bulkRequest = true;
+        params[key] = params[key].join( ',' );
+      }
+
+      break;
+    }
   }
 
   // Process
@@ -74,7 +87,14 @@ module.exports = async function SearchItunes ( {
     throw new Error( 'no results' );
   }
 
-  if ( first ) {
+  if ( idKey ) {
+
+    // Bulk lookup
+    if ( bulkRequest ) {
+      return data.results;
+    }
+
+    // Single lookup
     return data.results[0];
   }
 

test.js

@@ -68,7 +68,7 @@ dotest.add( 'Error: request error', async test => {
 } );
 
 
-dotest.add( 'Lookup by ID', async test => {
+dotest.add( 'Lookup by ID - One item', async test => {
   let error;
   let data;
 
@@ -91,6 +91,29 @@ dotest.add( 'Lookup by ID', async test => {
 } );
 
 
+dotest.add( 'Lookup by ID - Bulk', async test => {
+  let error;
+  let data;
+
+  try {
+    data = await app( {
+      id: [1477376905, 6448311069],
+      timeout,
+    } );
+  }
+  catch ( err ) {
+    error = err;
+  }
+
+  test( error )
+    .isArray( 'fail', 'data', data )
+    .isExactly( 'fail', 'data.length', data?.length, 2 )
+    .isUndefined( 'fail', 'error', error )
+    .done()
+  ;
+} );
+
+
 dotest.add( 'Lookup by trackId', async test => {
   let error;
   let data;