Move data fetchers to data.js file

Props @mtias for the suggestion

blocks/library/latest-posts/data.js

@@ -0,0 +1,18 @@
+/**
+ * Returns a Promise with the latest posts or an error on failure.
+ *
+ * @param   {Number} postsToShow
+ * @returns {Object}
+ */
+export function getLatestPosts( postsToShow = 5 ) {
+	const postsCollection = new wp.api.collections.Posts();
+
+	const posts = postsCollection.fetch( {
+		data: {
+			per_page: postsToShow
+		}
+	} );
+
+	return posts;
+}
+

blocks/library/latest-posts/index.js

@@ -7,18 +7,7 @@ import Placeholder from 'components/placeholder';
  * Internal dependencies
  */
 import { registerBlock } from '../../api';
-
-function getLatestPosts( postsToShow = 5 ) {
-	const postsCollection = new wp.api.collections.Posts();
-
-	const posts = postsCollection.fetch( {
-		data: {
-			per_page: postsToShow
-		}
-	} );
-
-	return posts;
-}
+import { getLatestPosts } from './data.js';
 
 function renderList( latestPosts ) {
 	return (